I've been looking through some greenhouse brochures and have been quite
shocked by the prices. Is it worthwhile buying a second hand one? Has
anyone done this - are they generally easy to dismantle and move?

You can usually pick up 2nd hand greenhouses in the local papers for nothing
or very little. If you have a day or so to dismantle and re-erect them,
they can be good. All my greenhouses were 2nd hand and free ;-)

Best,

- h