Skinnerbf

I completed on my self build about 5 months ago and claimed back the VAT on some of the materials. I was selling my other property which used to be my home before i moved into my self build, to help pay off the self build loans and mortage i have. The seller pulled out about 6 weeks ago and im been struggle to find a new buyer, ive been using the money from the VAT refund to help pay the cost of both mortgages etc However, i cant maintain this position for long and i need to find a new buyer for my old property. What im fearful of is that i may need to put my self build property on the market as well i cant aford the morgate on both. So my question is what happens if im forced to put my self build on the market as well, given that ive already reclaim the VAT for the build? Do i need to repay the VAT refund? Is there a min time limit on how long i would have needed to of lived in the self build before i can sell without having to repay the VAT that was refunded?