Don't be too disheartened, we were told at least 2 years for most of the allotments in our area, so we got ourselves on all the waiting lists, but we actually ended up with one after being on the waiting list for only a few months.
I think the key was that once on the list, we regularly phoned them up to see how the list was looking, showed willing and keen, and we then got a phone call a few weeks later to ask if we were keen gardeneers, so we'd obviously jumped the queue a little bit.
It's worth finding out who looks after the allotment, who runs it, etc. If they're close enough, you should be able to catch somebody going in and out to ask
