Porting my mortgage

Other

Hi
My mortgage product was coming to an end after being tied in for 2 years.
So i tied myself in with the same bank to a two year residential tracker mortgage.I was ok with it even though we were thinking about moving as i checked and it is portable. However today i was informed by santander that i couldnt port it as i had 23 buy to let properties and they dont allow more than five attached to any one name unless its in a ltd company. If i want to move i have to pay 7K ERC AND FIND ANOTHER MORTGAGE.
They had all my details including a spreadsheet of all my properties.I am thinking of going to the FOS if i get no joy from Santander, my circumstances havent changed in the last 3 months and in the mortgage offer all it says is that should you port your mortgage you must meet their criteria [that sounds vague to me ] Any help or advice before i tackle this beast.

Summary......Asked for new product offer subject to its portability 3 months ago...Bank had all my income and other details......gave me new product.........then refused me permission to port it 3 MONTHS LATER........Thats it in a nut shell.....If they changed their criteria in the last 5 months then i may not have a case, otherwise surely i have a case?

ANY ADVICE WOULD REALLY BE APPRECIATED

stur

thanks