If you want to be self employed just register with the tax man. Simple as that really. If you do that then you will be invited by HMRC to attend a couple of courses explaining what you can claim offset against tax and you ll find they are generally very helpful.
theres free help in your local business centre or business link.call the newly self employed help line at the inland revenue...google 4 the tel no.call tax credits...u will get tax credits every week ...amount depends on how much u earn and if yre single etc...u can get child tax credits aswel if u got kids. u may be eligible for rent help... call housing benefit.u will prob get a nhs card for free medicine dentistry etc.keep all your business receipts and bank statements, bills etc...
Register with the tax man and purchase public liability Insurance, which is quite reasonable. Make enquiries to pay your stamp.