my 2p worth.
It sounds like a good idea to do the books your self, in reality it isn't.
You have to be aware of what the taxman wants, how he wants it and lots of things like that, also you will loose time in doing your own books, get it wrong and i believe you can get a fine.
As the others have said, it will cost you for an acountant, but it will save you money, they will also save you money in the long run.
when i first started i kept my own "books" to show acountant, all is well, I gave up after my first visit because he still has o check everything, so why do the same thing twice? all i do now is to keep recipts in one folder and invoices in the other, (more folders as required) then take the whole lot to the acountant, believe it or not he likes it that way.
In short get an acountant as they will save you money as he really is on your side, dont forget he wants repeat business so if you are happy you will come back and also may refer your friends