You'll probably find that your local council provide free support to anyone who wants to start up a business - maybe go to your local MP or Citizen's Advice Bureau to find out. I used a free service in my area called 'Pembrokeshire Business Initiative' and their advice was very helpful.
If you are trading as a sole trader I don't think you need an accountant - something like Roundtracker can do all the work for you for a one-off free of £37. You just need to keep a record of your incomings & outgoings (which you would have to do if you had an accountant anyway).