Thanks guys,
The one I'm looking at has canvas and posts, but the canvas is old and leaking so it'll need replacing. I've found a place doing a set of canvas for 360quid (www.canvasco.com).
Should I just be looking for the 3 metal posts, or are there some extra fixings that are needed?
This one is a 51 with no winch, and is going for £5500. Is this pricey given the things that need sorting (canvas and tyres).