storbarnsförälder

A mortgage is also debt - lots and lots of debt. There's no point making it bigger unless it's absolutely unavoidable. While it is often true that oversrafts have punitive interest rates on them, it's not a universal rule - I have a 0% overdraft for example. I can't help you with the actual maths - numbers are not my forte - but it's worth while looking at the current and *eventual* costs of one type of debt vs. the other very carefully.