As accountans charge in approximately 6 minute blocks, you have to minimise the labour involved as much as possible. If you use an accountant, at least try and sum all you net figures, so all that is needed by the accountant is to work out the tax.
The net figure of your trades should be summed by yourself. It will take you a while, but imagine how much longer it'll take your accountant when he's not familiar with each of your trades as you are, to be able to match everything up quickly. Further, you're probably getting charged for every phone call, email etc he sends to you to clarfy answers to any questions you have.
My adice is that if you use an accountant, do as much work as you can FIRST, so all his time isn't spend summing up all your income and expenditure. That's the time consuming part that you can really save on.
