AIBU Being annoyed and setting rules

[Familyiness]

For my 21 year old daughter, her bf is pretty much always here, stays for weeks on end. I'm getting annoyed with her disregarding me, ie using the shower at gone 11pm, and there not quiet. Doing his washing now to, they never stay at his, as his room is too small. Today at least one of them had a shower earlier, then tonight the 2 of them went again, 50mins in the shower. She doesn't seem to understand how much this costs. They are off on holiday tomorrow but I feel I need to have words when she gets back about not taking the Mickey with showers etc.
For further context, he is a nice enough lad, I suffer with fibromyaglia and my husband has been off sick from work since Jan, he has had an op on his knee recently and it's looking likely he won't be able to return to work, as its not getting any better, so money is an issue as it is.
She works full time from home aswell, so 2 monitors and a pc running all day too she does pay 260 permonth rent, this includes her food aswell.
Would it be unreasonable to ask that showers are kept short and to one a day per person, and to restrict how often he stays over.

Why on earth are you doing his washing (& your daughter's....)?!???!?

@newbie202020 I don't put the wash on unless there is a full load. If they all washed separately, it would be lots of little loads. All the washing goes in one large basket and I put a wash on most mornings, if there's enough for a full load of darks or whites. They do their own bedding.
We have had a chat and I think she understands where I'm coming from now and is not having him over quite so often. He is also signing his tenancy soon, and his carpets are going in.
Also she is planning to move out possibly Feb time with a friend of hers in a house share, so she can have an office room for her work. She doesn't want to move in with her bf yet as they haven't even been together a year yet. They do seem good together and he does treat her well.

Bin space? I said it

Bins are emptied every 2 weeks. So takeaway containers every night fills the wheelie bins up, and there is 5 of us living here full time. And that's with me recycling as much as I can. They won't empty them if the lids do not close.
If you don't live in England then you probably don't get it. I'm Ocd aswell so having lots of rubbish hanging around will drive me batty.

"She works full time from home aswell, so 2 monitors and a pc running all day too she does pay 260 permonth rent, this includes her food aswell.
Would it be unreasonable to ask that showers are kept short and to one a day per person, and to restrict how often he stays over."
I think you are being taken for a mug op - £260 a month is peanuts. Particularly as that includes food and all bills essentially for not just her but him too.

And dont restrict showers to one a day....... A five minute (5 not 50!) shower every other day is plenty (unless they've spent the day rolling in mud/sweaty/work as chefs etc)

I would double the rent and ask them to be looking for somewhere else to live asap tbh. (for context I have kids this age and wouldnt tolerate the circumstances you are currently experiencing)