i have never bought any work off anyone , so im afraid i cant help you with that !
however , over the last few months i have been personally contacted at least half a dozen times by different people trying to sell me their rounds(inc today) , all supposedly in or near my area .
most of them didnt seem to know too much about the rounds they were selling , and strangely they were all exact numbers ie: 100 houses or £1000 / £2000 per round etc.
i hope im not being too cynical , and i hope, if and when the time comes to sell my round that all goes smoothly for both sides !