I think Mark covers many of the points very well - just the handling of vehicles, I guess. And thinking about it, I understand why Mark is struggling for a definitive answer - because there are a few ways to go about this and the best way probably depends on the exact circumstances.

The first year in business often is rather exploratory as there are so many things that are guessed at without much definitive information to help.

My suggestion is:
  • Keep a log book for each vehicle so that you can differentiate between business and private milage
  • Keep a record (complete with slips) of running costs - fuel, maintenace, licencing
  • Keep a copy of your HP/lease agreement handy, and keep track of your instalments

You will now have a clear trace of the detail required for your accountant to finalise your financial records in this regard and advise you as to the best way to manage these going forward.

Practically, this could be done as seperate expense line items in the business's "management accounts" (I like it this way because it is more likely you'll actually keep track of these things). Then when it comes to finalising your accounts with your accountant, these expenses can be reallocated if required.