The material is a vynil,there are 2 or 3 types used in cars,so you need the correct one to use.
If you are thinking of having a trimmer fit a complete new webasto from scratch then you will have to go to one who specialises in them and budget on no less than £1000+ vat probably more.
Any good classic auto trimmer should be able to make a new outer cover if they use the old one as a pattern,thats about £150 then it needs to be fitted to the folding framework,"another £100ish" and then fitted to the car "another £100ish!" Thats not including any headlining they may have to redo on it.
The way I did it a few years ago was to buy a complete webasto roof and 1/4 panels,then cut the whole roof off the rusty donor car mid door pillar for £125.
Removed my existing roof and headlining and fitted replacement over a dry weekend.
Its not cheap starting from scratch,and its near impossible to buy a perfect huntsman roof ready to fit,although if you do get one it may not leak,may have a few rips,and do you for a few years.
BTW!!
Martrim could not match my sample and the closest they had was not even close in colour or texture.
http://www.thetrimmingcentre.co.uk/page ... t_sunroofs