personally i think if they guy wants to sell
then you are only giving him a "goodwill gesture", thus i think 1 X the amount is enough, thats 400 quid
i brought some work late last year, now its allmost all gone, it seems the guy B4 me would just turn up as and when he liked, so my 6 weeks is too early for them and 12 is too late, so a fair few cancelled me, i dont mind, its not because of the standard of work i do, its just i am regular