Personally, I'd let him come round, or meet you at a mutual location, but at your convenience.
Explain the situation to him, he'll probably be happy to wait a few days to save £20 especially as he lives close. As an ebayer myself, I personally find it VERY insulting when people I live near enough to to actually collect an item I've won off them from won't let me come and collect! It makes me think they have something VERY shady to hide. I can understand if the person wouldn't necessarily want me mooching round their house, but how much effort is it to meet at the local pub car park, or petrol station? Certainly less effort then putting everything in a well packed box, wrapping it up, putting an address label on it, then crossing the palms of the local Post Office with silver in the vein hope it will get to its intended recipient in one piece! Nah, I'll always gladly wait a few days if I can pick an item up in person myself…