So I jumped the battery from the car, charged it for half an hour, then got it on the trickle charger for a few hours. Left it over night to see if it would hold charge and it did, put it on the bike used it for a couple of days with no problems. Have now left it for 24 hours and still holding charge. Hopefully keep me going for a bit whilst I sort the chain and sprockets.
Cheers all.