Yep, leave it to an accountant.
Mine charges £105 + VAT - I'm thorough with my day-to-day bookkeeping - and for that he does my profit and loss statement and fills in the tax return for me, advising what's due and when - I just sign and that's it.
I put aside for my tax monthly.
An accountant is fantastic and I would advise anone to get one - I know I would spend at least a day on my return (and several weeks worrying about it), so I'm not losing anything money-wise. Plus, he won't let you leave it to the last minute!
My philosopy is declare every single penny and back it up with a good accountant and you will sleep easy at night with a good conscience, you won't worry about being inspected and you won't get any unexpected bills!