If that were so, I'm sure my accountant woud have told me by now. He thinks I';m being too generous with 10% personal use and asked me if I ought to go 5%. I could justify it too, but I wouldn't want a load of hassle if HMRC ever decided to run the rule over me. 10% I can show them. 5% might get a little picky. In reality I'm guessing it's about 7.5%.