To think this is unreasonable?! Or am I out of touch

They definitely ABU. They shouldn't expect you to get eyestrain and they should realise that you are doing them a favour so they can see DD.

Your solutions are

don't go there any more, because you can't work in the dark

buy a light for your laptop and take it with you. I used to use this one when I did onsite work - one client had a really dark office. It just works off your computer USB.

https://www.amazon.co.uk/Music-Stand-Light-Gear4music-LED/dp/B018W5JN2K/ref=asc_df_B018W5JN2K?mcid=b36fd69d8d7e3d58a5425a2c26381cfe&tag=googshopuk-21&linkCode=df0&hvadid=781426097673&hvpos=&hvnetw=g&hvrand=1998429395345184518&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9045297&hvtargid=pla-2455881725169&psc=1&hvocijid=1998429395345184518-B018W5JN2K-&hvexpln=0&gad_source=1

Going over there is too difficult. You don't get as much work done and have to catch up in the evening and they aren't allowing you to do your work in a suitable environment.
Stop going.

I’m approaching this with science, but as you are not really using your parents for childcare as it is paid elsewhere you could say

”I get that you prefer to make your own choices in your own home, but I from my point of view I am accommodating you by bringing DD over and using my own time in the evenings to catch up for the time spent driving (which I don’t begrudge, as it is nice for you and DD to have the bond), so it only seems fair to give me good working conditions (which you shouldn’t begrudge, as it is nice for you and DD to have the bond). Tell you what, if you feel put out by me having a few spotlights on, we can have a formal agreement about it - over the next year, you can calculate the cost of the electricity and any spotlights that are broken as a result of me having them on and I will calculate the petrol money that you owe me for the additional cost of me driving to you rather than to nursery, then whoever owes who money can pay up”

Hopefully that will stop the nonsense!

Sounds like they 'prefer' lots of things whether it suits you or not!

Seriously, this is your life now. Just do the things you want to do. See them on a Saturday? Say the long drive and working without a light on isn't working for you any more, so they can come to you?

You're the parent now.

Some people just enjoy sitting in the dark. I too need lighting, whether for WFH or TV. My partner's mother loves to sit in the pitch dark but for the TV, and when I had to go over there to work once, I had to do it in the dark, and I felt so ill when I got home. Headache and strained eyes. A lot of people where I live in the NE seem to turn off all the lights come the evening, and just use the TV light. I find that so odd.

Here you go OP:

https://www.screwfix.com/p/lap-rechargeable-led-work-light-1000lm/613KF?tc=UA8&gclsrc=aw.ds&gad_source=1&gad_campaignid=20283917959&gbraid=0AAAAAD8IdPzEEKwEvgxYlHy8LDYihlVsP&gclid=EAIaIQobChMIpJjbkr-BkgMV0JCDBx2hnANmEAQYASABEgKw_fD_BwE

Of course it’s unreasonable. My parents both did the whole ‘we’re so poor’ thing, so weird. My Dad claimed that he would need to get a mortgage to buy a bungalow (he lived in a house but wanted to downsize and bungalows were maybe £30,000-£40,000 more than his house was valued at) well he died unexpectedly and without saying how much money he had, we had to pay inheritance tax! And I had sat commiserating with him that he couldn’t afford to move 😂 My Mum does the exact same thing, says she can’t afford £20 per week towards care home fees for her Mum but forgets that we know she sold her house that was paid off, had a pension lump sum, retired at a time when retiring was actually possible without a side hustle, has zero housing costs and hasn’t been anywhere since that would cost more than a tenner, eats frugally like it’s the 1950’s, shops in charity shops etc (100% sure there are no hidden expenses) All of which is their right but it’s annoying isn’t it? It’s lying really and you’re expected to go along with it. It must be a generational thing, though I expect your parents are younger than mine. Let’s just say I’ve enjoyed spending my inheritance. Every time I feel guilty I think about not having any days out as a child, being a bit hungry because we lived so frugally or having clothes as a birthday present etc when we were perfectly able to live a nicer life.

Get yourself to Screwfix and buy a rechargeable work light that does 5 or 6 hours. Probably cost you less than £40.

They are being unreasonable but from what you described they are also inflexible so it is a catch 22.

You just need to keep repeating the same messages and follow through on consequences. Put your needs before their wants.

You need to work. You need light to work. That’s not negotiable.

They want to see DD. They want to see her at their house. They want it to be during the week instead of her going to nursery.

You are happy to accommodate their wants but only if they accommodate your needs. If it doesn’t work for them, you revert to using nursery which can meet those needs.

It could be the spotlights are hard to change,some of them are.

however some people are so weird about lighting. My sil is. She wants it dark, every evening, even when hosting, we sit there by rhe light of the tv, which is just playing music, once I switch the side lights on , as we couldn’t see each other or our drinks, and she went nuts about how she didn’t like it bright. It was a side light, a solitary table lamp. Once they came to my house when we were out, I’d left the side lights on for them, when I came back they were sitting in total darkness with them switched off.

its the oddest thing.

They’re entitled to their opinion and to run their house as they see fit.

I would respond by stopping taking her over there.

You’re not being unreasonable or controlling OP. Frankly I can’t imagine telling one of my DC they couldn’t put the light on if they were visiting at my request, but each to their own. If they want to put conditions on your visiting that’s fine but then they also have to accept the consequences. They don’t get to have it all their way. In your position I’d stay at home, put your DD in nursery and presumably gain the rest of your evening back with her too. I do believe GP relationships are important but it’s not your job to facilitate a relationship entirely on their terms.

Perhaps you could see them some weekends instead?

Why don’t you go after working hours?

The solution is that working there doesn’t work for you so either your DD goes to nursery or else they come to your house.

Buy them some spare bulbs and offer to go an change the bulbs if they go. It is odd behaviour though, in my opinion.

Buy a head torch.

I said that to them and they said I was controlling and unreasonable. They prefer DD at their house rather than coming here

So you tell them that they are being controlling and unreasonable and that you prefer getting work done in adequate light so you won't be coming anymore.

Who made them King and Queen of what you do?

If they are stupid enough to lose contact with their grandchild because they want to die on the hill of not putting the light on, then that's their decision

Do they have any issue with you plugging your laptop charger in? Or is it really just the light bulb?

I think it’s mad that you’re paying for full time nursery but:
1 regularly not using a day that you’ve paid for
2 going to your parents house because they want to see DC but won’t go to your house EVEN THOUGH DC SHOULD BE IN CHILDCARE YOU HAVE PAID FOR
3 working from your parents house to facilitate that nonsense and waste of money

tell your parents the mid week visits are going to have to stop, that you can’t keep taking DC out of nursery like that (make up that you’re risking losing her place if needs be) and put a stop to all of this.

Sounds as though what they actually mean is that they aren’t comfortable with you using their home as a workplace. I would find a couple of nice coffee shops nearby and split my day between the two of them, assuming it’s too far to drive home and work from there. YANBU they sound stuck in their routine/inflexible but a lot of people get more intolerant to change/infringement as they get older (I’m 50 and already getting to be quite the grumpy arse 🤣)

Ignore the guilt trip, it’s shame the can’t be bothered to come to you, it’s a shame they can’t be bothered to visit to have a relationship with your DD. Push back and put in boundaries. Don’t run yourself ragged. You already work full time with young child.

The problem is, whether or not you've paid for nursery, they are providing you with childcare.

In your situation I wouldn't feel especially delighted or grateful, because you're doing all the running here, but people tend to see things from their own perspective.

Are they this ridiculous in other ways, OP?
as an isolated bit of batshittery it’s VERY odd.