Thanks for all your help guys. Maybe because I'm in England and we get whacked pricewise for American products but the Marshall actually works out much cheaper than a THD Hotplate. Typically i can pick up a power brake for about £180 ($317) whereas a THD will cost me £250 ($440). The weber mass looks like an interesting piece of kit and judging by the american dollar prices should be quite a bit cheaper - unfortunately I don't thnink they have a UK distributor. For anyone else who is interested in the Weber though there is an interesting review here http://www.legendarytones.com/mass_attenuator.htm