If any GoYers live near you, Pippy, then I am sure that they will respond.
Failing that, try Landshare, a web site that connects people like yourself with people whoo want some garden ground. I tried it a few years ago and had several responses.
http://www.landshare.net/index/

Thanks bulbaholic but i'm not brilliant wuth computers and had no luck with that :-(

If it weren't for the fact I live in London, I'd have taken that on...

You could try getting in touch with your local allotment association, allotments are much sought after these days and there are usually long waiting lists, so may be worth a try.

If the allotment association doesn't come up trumps it might be worth actually getting someone to help you to register with the Landshare site as it has a long list of people offering land and another of people looking for land.

Why don't you ask the immediate neighbour if they would like to buy it from you - to extend their own garden/property ..... i'd bite your hand off if you were MY neighbour.

One of the GoY members did this a couple of years ago and he's chuffed to bits with it.

Old fashioned way of doing things place a card in the local paper shop. But before allowing anyone, go and check out their garden.

That's good advice, Pimpernel!