Hi James
I'll put my credentials up front - I am an independant mortgage broker. For added peace of mind I am one of very few brokers approved for membership of the Trading Standards Buy With Confidence scheme. (www.buywithconfidence.info).
Most lenders who work off income multiples will take a years monthly payments from your income before multiplying your income to establish what you can borrow. This will probably take you out of the criteria of alot of them, unless your parents are really generous.
However, to answer the 'cat in hells chance' question - YES - assuming you can raise a 5% deposit and assuming your loan is around £300pm then finding a mortgage for you to buy at £90,000 should be feasible.
From there, you will have more and better mortgage options the larger your deposit becomes. The size of a deposit is usually considered in bands - 5%, 10% 15% and as you break through each band you can benefit from better rates/better fee structures and more lenders accepting you.
Give me a call if you want a chat - 01489 784022
Adrian Garside