Changing topic - if any caravanner runs out of butane next year, I can tell them where NOT to go to a replacement. The caravan and camper van shop on the main road out of town, just near the Broadstairs campus of Christchurch univesity. They quoted me £27 and odd for a refill for a 4.5kg bottle of butane. The proper price is under £15 - and here is a link to a camping chainstore sellig it for even less: -

http://www.gooutdoors.co.uk/calor-calor-butane-4-5kg-camping-gas-refill-p132716

I HATE swindlers like that.