Did he specifically lay out NO Callers in his auction terms ?

If not he has no right to refuse you as he is altering the contract of agreement upon the closure of the auction between you and him. He is allowed to change any postage fees upto a reasonable amount but not AFAIK refuse callers if he didn't state it.

I'd ignore all his mails call round with a cheque, check the item out, and if your happy with it call round in a further 5 days to collect it once it has cleared. If your not happy with the item on your way home call into bank and cancel your cheque. Job sorted.