Using a software package like quick books enables you to maintain your books on a monthly basis and track your cash, P&L and balance sheet. Doing this yourself or using a bookkeeper will be cheaper and more efficient than once a year using an accountant to put everything together in one go. I maintain my accounts myself and produce a monthly overview so I can track all income, costs, cash and know how much I owe HMRC at any point in time.
You can then use an accountant once a year to check and file your accounts + tax if not comfortable doing it yourself. Having all the data in quick books should reduce their fee compared to having them doing all the work. If you have a straight forward business and have used an accountant for the first submission you should be able to do all the work afterwards yourself.