The garage at Union Mills sells pump LPG (not sure about bottled) but worth a try. Although there is no longer an official Calor gas stockist on the Island or there wasnt last year when we were over for the MGP we exchanged a Calor bottle like for like at the Garage adjacent to The Sidings pub in Castletown. They were quite happy to do this as long as there is a valid pressure test date on the bottle. Hope this helps.