We carry out conversion and repair work on our own vehicles but I am unsure how to account for the costs. I have raised an internal zero rated vat invoice so that my stock is adjusted and labour accounted for but not sure if this is correct or if I need to do a journal to clear the balance from my sales ledger?
You need to engage/speak to your accountant before you make a huge mistake on several levels with this one, one extremely serious, (and possibly even other basic bookkeeping mistakes)as your understanding seems to be miles adrift of accounting reality and could cost you dearly in them fixing it all at the end of the year/other issues in future.