Home Improvement Loan/Mortgage

Hi there

Hope someone can help.

Have a house on a mortgage - mortgage £51000, value of house approx £165000.

Thinking of extending - value approx £45000 - value of house will then be approx £210000.

My wage £17000, partner newly self employed so no accounts as of yet.

Rang existing mortgage company, Nationwide who say based on affordability can't lend us anymore.

But we have been overpaying for many years which is a similar amount to what the existing mortgage and extra borrowings would cost.

I said that we have proven that we can afford the amount as we have been paying that amount for many years, but they said that that is irrelevant and that it is based on affordability, not equity in house or proof of previous payments.

I am so upset, is my dreams of an extension up in smoke?

Any help would be greatly appreciated.

Thanks in advance. :)