thanks heaps for that, much appreciatedThey tend to be horrifically expensive to buy new.
CQS has them (Heidelberg West, 9458 3488) but they'll want your first-born for them. eBay is worth a try, if you can wait. They are usually called pluto or jockey boxes. You can build one yourself cheaply enough - other folks here can probably even help you find parts - it's basically either a coil of stainless tubing or an alloy plate with internal channels. Add a couple of fiitings and an esky (and ice) and you're good to go.