Mary
This is something that myself and my wife may possibly be interested in; we're both animal lovers and have a St Bernard, a Pug, 6 moggies, 2 chipmunks, a hamster and a mouse between us.
We haven't done pet sitting before though (although we did care for a dog for a few hours when someone rang our doorbell and found it running around in the road outside our house, until the police managed to trace its owner after we phoned them), but would certainly consider helping you out if you're stuck, and if you don't think it's too much of a mad house for your dog!
Also, I seem to remember an advert on the wall at our local vets,
http://www.pearlvetgroup.co.uk/ for someone local who did pet sitting from their own home, if you'd prefer someone with a bit more experience!
Kind regards
Richard