I sold one on ebay earlier this year,made £400 and I pulled the ad and sold it at that to the highest bidder as it had damage that I didn't notice when I listed it.

That was after 2 days of a 7 day listing so I quite believe it would go to £500

Paul Linfoot was about as helpful as my dog with regards to valuing it,no reply to the PM I sent him through the RSOC