What have you said on tax form,wouldnt that be best option??
or have you not been earning enough?
i think ebay is the best bet,set up an account,maybe buy and sell a few items.so you know what your talking about if they ask...
just say you have been a sole trader and was doing well but now business has declined and you want something more secure and permanant,been self employed just isnt for you any longer..
And you would love for there, company to take you on board and join there team....