I have a portable tracker mortgage with Santander. We want to sell my flat and move to a bigger house. Although my flat has about 100k equity and we have another 30k in cash saved, Santander will not lend me another single penny as it goes on affordability and my freelance earnings have not been so high over the past few years because I had DS. They won't touch DP because he is a professional gambler and so zero-rated for tax. His earnings don't count at all.
So I will sell my flat (all in my name, my mortgage) and transfer the mortgage to the new property but we will have to find all the extra money and are currently about 25k short. My bank have said they will lend me 25k. WIll this affect the mortgage transfer? Do they need to know what borrowing I have even if they're not lending me any more money?