Christmas time off

Nope. I have kids but I expect it to be fair and if everyone can’t be off then it’s rotated.

be prepared for if your manager says ok will alternate for those women to say that it’s too late for them to make arrangements for this year so it’ll have to be next year (which will never happen).

if they do try that, you have to then say that as you worked last year, you assumed you wouldn’t have to this year so you’ve also got family arrangements.

this is where your manager or one above them needs to take emotion out of it and go down a fairness route of it’s alternated but people can swap if they’re happy to.

This is why it shouldn't be left for people to decide between themselves. It's a complete cop out by your manager because they don't want to be the bad guy.

Your manager should decide, based on some fair principles (e.g. rotating who has to work each year).

I’m confused. If you are working Xmas Eve and the days “around” Christmas then you aren’t actually working on Xmas Day or Boxing Day are you?

I wouldn't bother with this, OP doesn't need any reason to want the time off other than she wants the time off. It's nobody's business whether she has a relative at death's door or if she wants to spend the day in her pants eating smoked salmon.

I had this issue in my old job - people with young children always got priority, no matter how early you put your requests in.

I ended up leaving when someone with two children managed to get Christmas Eve and Boxing Day off, even though our contract specified that everyone had to work both (busy retail job) - it just took the absolute piss.

I wasn't the only one to hand in their notice - there's a new manager there now so I have no idea what it's like nowadays.

It's your manager's job to manage the drama. Refuse to work as you did it last year. That's only fair. You could negotiate and offer to cover 23rd and 24th if they work 27th, if you're not overly bothered, but you should absolutely get some time off over Christmas regardless of whether you're a parent or not.

Absolutely you’re right. I would just take the approach of obviously you won’t be working those days again as you did them last year and now have plans so they need to decide between themselves who’s doing it

You'd be perfectly within your rights to raise this with your manager. There should be an allocation which is fair to everyone including consideration of who had the time off last year.

Not fair at all - in our work we all request what we want off and I always work some of it ( Xmas eve this year) even though I have three kids.
Some request all off every year and get it but I can't do that as I don't think it's fair

Tell your manager that the system has to be fair.
And if your colleages bitch about it, have a (made-up) story ready about how one of your close family members has an incurable health condition and this will be their last Xmas and they really want you there... or something like that... and see if that changes their attitude

Perfectly reasonable to expect it to be fairly shared out - like you say, people who don’t have children can still have family they want to see! Manager is abdicating their responsibilities - if people don’t agree easily between them on something (and on this I wouldn’t expect them to) then manager needs to do what their job title implies and manage by imposing some sort of fair allocation, rota scheme or whatever.

Absolutely not. This makes me so angry.
Apart from anything else, what if these colleagues of yours said 'people with kids should take priority' to someone who desperately wants kids but, for whatever reason, can't? (I'm assuming from your post that this is not your situation but I'm so sorry if it is).
I'm child-free by choice but can still see how offensive this is.
The only fair way to do it is by yearly rota, and I'd say that to your manager.