At the moment, I have discovered if you put a refund through as a negative (same nominal code etc as sale), it becomes a purchase. This means that the sales figures are overstated eg. in VAT. Apparently, in order to prevent this, you have to put a journal entry for every refund.
This seems like a fundamental flaw - Sage does not have this problem.
I never knew this, is there an article explaining this on KF site?