Thanks for the help, managed to find one cheapish so hopefully when that turns up it'll go on without much trouble.
I'm pretty much a complete beginner, but I can trackstand well enough for mtb purposes, i.e. waiting for people to open gates, but it's not really cutting it for trials so that's what I'm concentrating on at the moment. Since I've not got a back brake anyway I've been practising either with just the front brake or both brakes off which got me wondering whether there's an advantage to getting used to doing it without using brakes? My thinking is that since balance is pretty damned crucial that learning to rely on the brakes to stop myself pedalling forward in trackstands might be a bad habit to get into, any thoughts?