In reply to sleavesley:
I discovered by a thwarted attempt to fit them that they don't work on smaller frames. I had a small Dawes Giro and found that the size of the rear triangle was too small for the minimum distance between the fixing points on the guard. Attaching it at the top of the seat stays put the other end well below the chain stays and barely off the ground.
I eventually went for race blades, but they are an arse to keep secure. I think getting a bike that will fit some chromoplastics and having a shop fight with getting them on is the best bet for full mudguards.