Oh, OP, sometimes I think I'm reading this on another planet.
As an example, someone wrote:"Sorry op but you sound like a spoilt entitled brat. I never had ANY help with my dc at all. Your kids, your responsibility."
This is the main problem on MN when it comes to do with childcare. People want to deny others the things that they themselves never got. It's pure jealousy. That's all. If people who say those things HAD had parents who helped more with the kids, I doubt very much they'd feel the same way.
You're really not asking for much, OP. You work 4 days a week, your other half works away (been there done that, it ain't great, you have my total sympathy) and you're asking for a bit of babysitting for a few hours no more than what, 3 times year? For work reasons. You don't want to go and have a spa day somewhere, or even go away for the night with your DH
for some much needed couple time. You are asking for them to look after THEIR OWN FLESH AND BLOOD for a few hours on a Saturday when childcare is kind of non-existent! And your DH is away working! Not on a stag do!
The people who have called you spoiled have left a really nasty taste in my mouth. They're all so cold and unfeeling. I'm glad they're not my parents.
And I'm saying this as someone who was a SAHM when my kids were little so that I wouldn't have to ask my parents or IL to child mind during the day as a regular arrangement. I realise it's harder for older people to mind kids. We were so skint because of it. My mum picks up DS2 after school one day a week now he is older and I'm grateful for that because after school care is nearly £12 per session. But they do go away themselves regularly and the agreement is that they should not restrict themselves because of picking DS2 one day a week, so they don't. Instead DH picks DS2 up from school when they are on holiday.
They have the kids overnight every 3 months or so and all enjoy the benefit. It's called being a close and loving family and sharing warm relationships. I just don't get the MN stance on this at all.
I've never asked my mum to babysit so that I can go on a shopping trip, or on any kind of pampering session for me - DH does that. But she acknowledges that every couple of years DH and I feel the benefit of 2nights away in a hotel and happily has the kids for us, as she remembers what it's like to be a parent! She will also happily babysit for any appointments I have eg smear and mammogram where it's awkward to take kids.
I do not take the piss. I do not want to take advantage of her. But when your own DD asks for help with a difficult childcare and situation and you turn them down, then you have to be a special kind of selfish.
I CAN understand your mum wanting to host the visitor from Ireland. As has been suggested, I would just compromise and o when the visitor has left, that's all. Your mum and dad DO still need their own life and interests especially if your mum still works (mine is retired and hasn't worked for years anyway before that), and it's important that they keep up with friends. So, if this were me, I would gladly let my mum and dad enjoy their visitor without me being there, and then go after he's gone. Don't forget the visitor might also feel awkward if you are there with your kids when he is.