Married for 9 months! Who gets what?

Hi everyone, looking for some advice!

where do I start…

in 2015 i met my stbx, relationship started and living together by end of year. In house I already owned outright, brought with inheritance back in 2013!!
We go on to have two children. During second pregnancy we decide to get a mortgage on my property to do some renovations, I add her to the deeds to be able to get a joint mortgage, only small amount (27% of house value) so when I done the transfer of equity we agreed on 15% to her. I’ve then paid every mortgage payment up to date and paid all household bills, upkeep and childcare cost.

we then go on to marry in 2019. 9 months later she leaves and moves in with her mum. Reduces her hours at work to be able to claim UC and get her rent etc paid so she doesn’t have to stay with her mum. She now only works 10 hours a week. We have child arrangements sorted and I pay maintenance and childcare costs.

now she’s harassing me for money out of the house. Where do I stand? She is seeing a solicitor tomorrow, is there any chance she is entitled to more than the 15%, or not even that much. I understand she will want something to come off the deeds and I will have to remortgage in my sole name but I’m very reluctant to burrow more, after she left and the short marriage.

ANY help/ advice or similar situations would be grateful! If you need anymore info fire away and I will answer all.

Not enough details but it's effectively a 5 year relationship that has 2 children under 5 at the top of the needs list. I'd say 15/85% seems fairly unlikely to be the outcome on the basic information provided if it's one of the few assets available

It’s the only asset available, I have minimal savings that will surly be eaten up with legal fees sorting the divorce, have no debt apart from mortgage, where as she has a few debts I believe and car finance etc. She does earn less then me but that’s only through choice. Biggest issue I’m worried about is it getting split so that neither of us could afford another property, she will loose her benefits and I don’t earn a great deal so won’t be able to get an equivalent house after current mortgage paid off and equity split any more than 15/85. She has agreed on 15% but I’m worried soon as she gets legal advice they will obviously push her to get more. Could end up with me in a flat without space for my kids to stay and her unable to claim benefits due to lump payout and also unable to get a mortgage because of bad credit and very low earnings, don’t see how that would benefit the children at all, because at then end of the day I hope they would come first in any judgment, I hope it doesn’t get that far and we just do what we have agreed, just looking for worst case scenario. Thanks for a response!