I had my stipend accepted as income without a problem by the Halifax. All they ever asked for was proof of ID! Abbey and HSBC also didn't seem to mind in principle. It does seem to help to have a large deposit and so a lower loan-to-value (LTV) ratio. Essentially, a low LTV means they'll get their money back if they have to reposses and sell quickly, so they don't really care whether you can afford the payments.
If you are still having problems getting a mortgage, then self-certifying is an (expensive) option, and one I would avoid if possible.
Speak to a good IFA who can search the whole market and I'm sure you'll be able to find something