@1000rr
You can improve that roof 100% with a few ยฃยฃ spent on black shoe polish .
I've done all the roadsters i've had this way , some were a lot worse than others
That looks particularly bad but id say no worse than the silver MR i bought 2 yrs back which was truly shocking

get yourself some of these https://www.ebay.co.uk/itm/4-x-Cherry-Blossom-Leather-Shoe-Polish-Black-Liquid-85Ml-Ready-Wax/223377754559?hash=item34025a09bf:g

MkAAOSwz2lXBbAC . f
Cut the tops off & pour contents into a container then simply paint liberally onto the fabric with a 50mm paint brush ( after its had a good hoover , scrub , clean & is dry) .
Mask up paintwork before you start