Overtime - if you can prove it is regular i.e. shows up on most monthly payslips then they should take it into account.

IIRC they work on affordability more than salary x % basis nowadays. With reference to your salary, £140k (over 25years) will probably cost you £750 to £850 / month for a repayment mortgage or £450 to £550 for interest only mortgage (after any discount period). You need to be able to prove to the mortgage co. you can pay the mortgage and then all your other bills (council tax, water, gas, elec) plus food, car expenses (ins and petrol), clothes, and other living sundries such as socialising etc.

If you can't stretch to this then you could do with go in with one or two mates on an interest only basis to get on the ladder and it help to avoid chucking money away on rent - as although you are not paying off the capital, you can do improvements to the property and also hopefully will have gains in equity (the market is still going up - slowly). Presumably you don't have a g/friend who wants or is able to move in?