My local branch of T J Hughes in Shrewsbury is selling large household storage boxes (ex-Sainsburys) made of twin-wall plastic for £2.99 - they make fantastic mini cold-frames, especially to use inside a cold greenhouse on frosty nights. You have to put them together yourself with plastic studs and there are no instructions (?) but it's fairly self-explanatory once you get going. Hey, if we can put greenhouses together we can do anything! ;)
