I had a good chat with him on the phone. He was an oldish chap and had no idea of the hours, but said it didn't smoke when running so was in fairly good condition. He also suggested that I was crazy to consider driving it home to Gloucestershire from him though, so wasn't at all pushy with his sales pitch!
I've emailed AV - going to contact them when it's in stock but not holding my breath on the price. They're going to sell it for market value, which by the time I've added a tipper and linkage will be too much money as usual.
Epic fail on my part. I should have just bought the bloody thing and broke it up if it was knackered.