No, I don't have any, just some advice!   In the week before Cambridge there's usually a rush of people having to offload tickets for reasons of some crisis or other. Here and uk.music.folk are good bets for finding them. And you can always try eBay. Failing all that, just turn up. There are always tickets about, in fact there used to be a tree at Cherry Hinton where people stuck notices with details and phone numbers.    Good luck!