You don't even need an accountant if you're able to read and use a calculator. Read the HMRC site to find out what expenses you can claim for, and use a calculator to add all yours up. Tax returns want your turnover, your expenses and your profit. If you ONLY have an income from one type of self-employment, it's very simple.
And now that I've typed that, I realise I need to do my 14/15 accounts soon...