Hi there, my 6 month old boy used to do the same thing! I used tiny pieces of schmackos(smelly treats) to entice him out of the driveway, but started off first by carrying him about - over to the neighbours, across the road, just to get him used to being in different situations.
Just take it slowly, and befoe long he'll be mad for it. I also used to have Indie on his lead when I weeded the garden, or took the bins out, just as much outside stuff as possible at first.
Shona
