Hello Richard
Agree with Sabre; most accounts can be carried out on an Excel spreadsheet c/w some good organisation. I also keep paper copies of all invoices for fees etc and copies of all expenses. Everything is then handed over to my accountant at the end of the year in a well ordered manner, so that it saves them time to produce the accounts in an acceptable format for HMR&C. Another way maybe just have a word with your accountant and get an idea as to how they would like your accounts presented in the first instance.
The other thing to remember is that the accounts that you may need to effectively run your business may be somewhat different to the records the accountant needs to submit to HMR&C, so it is very important that you do your accounts in a manner that assists you in managing your business and in most cases the accountant will extrapolate the data from those accounts to the accounts / sums required for HMR&C.
Another thing to discuss with your accountant is paying a relatively small fee for an insurance which covers you against any possible tax investigations carried out against you by HMR&C, as if this does happen, such work can be extremely costly and time consuming, so this relatively low cost insurance may well be well worth considering
Good luck with your new life as a sole trader!