Good news its in the lenders interest to lend over a longer period of time so 35years wont be an issue.

Your income however is an issue for the amount youd like to borrow, ever with a bit of give and take you still wont get anywhere near £140k.

The only way it would be feasable is with a 15% deposit and a self certification mortgage.

Or you could apply for a self cert mortgage state that you will be puting 15% down. After the mortgage has been accepted apply for a loan, for thr difference between your actual deposit and the 15% you said you would place as a deposit.

Makeing it affoardable shouldnt be an issue if you chose interest only mortgage until your equity in your property increases, when it does remortgage and clear your loan.