Ex will not sign TR1

I purchased a house with my ex partner 18 months ago. I paid a large deposit over £200K deposit from sale of my previous home and we jointly had a small mortgage of £130k. After 8 months our relationship broke down and my ex partner moved out. That was a year ago.

I have attempted to remortgage house so mortgage in my sole name and have been awaiting my ex to sign the TR1 for almost 6 months. He is playing games, and wont let go. Sought advice from a solicitor who advised to pay him off.

Over the past year, he has paid nothing for mortgage, buildings insurance, council tax etc and all the while I am getting into further debt.

I have asked if my ex wants to attend medication, or asked if he wants to sell the house and he has ignored Communication.
Finally he 'took the bait' and agreed to sign on return of a lump sum. That was 6 weeks ago and it seems he has resumed to non-communication and 'do nothing' mode.

I have researched ToLATA applications, schedule 1, etc but we are not married which makes difficult. I have two children from previous marriage of junior school age.

Any advice on next steps, I really cannot afford any more legal fees and am happy to make application myself but need template or guidance on what court application form?

Many thanks