I had to put my two pennith in on this one. I need a new cratch cover but need to be careful how I spend my money as I'm a pensioner with limited funds. My cratch has no windows but has 4 zips for roll up sides. I started getting quotes a few months back and the average was £700+. I did find one at £550 but like the rest there was a waiting list of several months so I gave up. Move forward to now, my cratch is very very poorly and won't last the winter. I cannot afford £700+ so did some digging locally in the north west. I have not had the job done yet but found a guy with lifetime experience who quoted, depending on material and refinements. His quote was from £200 all the way up to £400 for the crème de la crème.
The lesson is shop around, you don't have to pay silly money.