Mum wants to sell property I live in ASAP

No, you were stressed out. Understandably so. And it's not nice to promise A and then change the plan unless she has financial difficulties she hasn't told you about.

Did you ever pay her rent? Or was the flat rent free? Morally, you should replace the taps and lino. Your damage, your cost. No?

I would not replace any taps or lino

To clean taps, soak an old cloth; tshirt in white vinegar & wrap round the taps
Thus should remove stains

Partner asking me to ask her for the money to have available to pay solicitors asap when bill comes but have a feeling it won't be there.

Ouuchhhhhh......

And his parents have bailed.
And he has given rental notice and is moving in to her flat for free?

I imagine she is suspecting an unequal relationship - possibly some 'future faking' behaviours and a potential 'cock-lodger' situation....so shes possibly putting a spanner in the works to protect you - holding back the £10k and pulling her flat from under him....

Whats his relationship history and financial situation?

Does your DM like and respect him?

It's common to have part of your money tied up to get higher interest rates. If she takes it out before the maturity date she'll lose some or all of the interest.

Going on the market is a long way from a sale. Your purchase is underway and your mother will be paying service charge and other bills after you move out.

She's giving you a lot of help but you want it all on your own terms. She hasnt broken any promises, unless she specifically said the money was available anytime you asked.

So you’ve been living rent free in her flat and you’re annoyed she wants to get things moving selling it now you’re moving out. You’re also annoyed she’s not giving you as much money as you first thought. .and you’ve damaged the flat and haven’t put it right yet.

Then let this be a lesson to you both to stand on your own two feet.

Maybe both his parents and your mum are touring of you both taking little financial responsibility for yourselves? You both do seem to expect a lot of other people's money.

I still wouldn't do it

Think about this sensibly and rationally OP.

You’ve had an offer accepted on a property (I presume if you’re instructing solicitors) but no date yet for completion and moving in. so what makes you think your mum Is going to have her flat on the market, under offer and sale processed and completed before you get yours done?

yes it is possible if she sells cheap to a cash buyer but it’s not that likely.

so calm down, tell your boyfriend to move in as planned and then talk to your mum about moving the goal posts on a few things.

It really depends. If she finds a buyer quickly; and searches in your area are not backlogged, it could be six weeks or so. If one of those things isn’t true, it could be six months.

I do think you could ask her why she’s now in a rush to sell, that’s quite a normal question…. I can understand why your partner is put out; under the circumstances.

It took us about 7 months from deciding to sell to actually completing. If you are already in the process of buying then her putting the flat on the market is probably fine. I get that it is annoying and you don't want to be worried it will sell and complete before you but it isn't that likely. The change of plans is unsettling though

Pragmatically, she's probably thinking that you and BF will soon be on your way, and she'd rather not have the flat empty longer than necessary. So it makes sense to put it on the market in the new year and take things from there.

Maybe she needs to recoup the sale value to cover what she's contributing to your new place?

You and BF seem to have reacted quite dramatically, rather than having an open conversation with someone who's being very generous to you and not given any pressure.

In the current market unless it is truly remarkable in a very desirable area. It will not go quicker than you can be in your own house.

its a stressful time but hope it all goes smoothly for you, even if it does reach a point where you need to leave before your house is ready (it won’t) it won’t be very long. You’ll be ok

taps and lino is a small job. Focus on the true issue

Is doesn’t sound like she is communicating very well with you. I wouldn’t want to leave my daughter feeling anxious about all this.

What is your relationship like usually?

For the money do you mean she offered a larger amount and then changed it at the last minute?

TBH from the little you have said I would be feeling a bit unsettled too.

Are you paying rent to your DM?

In any case the market is terrible at the moment, realistically you won't need to be out by June. That's enough time isn't it? I'd assume a free stop gap would be 3-6 months.

If you've got mortgage approval and so on. surely it's just a couple of months before you move into your own property? Unless she's going to offer it cheap to a cash purchaser it'll take your mum two or three months at least before she completes and you have to move out.

From the flat going on the market to offers being accepted and surveys done and all that you're probably talking 3 months anyway. Can you just agree a date with her for when you'll move out? Like 1st march maybe?
If you can't move into your own place by then it's enough time to find an airBnB or something temporary like house sitting