Thanks so much for the reply guys! I usually drive once, sometimes twice a week. And i will have the roof down 80% of the time. When down, i will always put it back up that night... so never down over night, probably only down for max 8 hours. Then stays up(and clamped) for rest of week. In a garage.
Maybe when i leave it up, i will try NOT clamping it down? And see if that helps. And also add some time parked in the sun as you guys suggest. The lines don't feel like creases as such, which generally mould away in the hot weather... more like cords in the material.
"Just hope the outer vynil hasn't delaminated from the cloth backing."
"I think it's more likely that it's a fabric tensioning issue, with the 'lines' lining up with the fixing staples to the welting strips around the body shell, rather than a delamination issue."
These two points sound interesting, but not like an issue that the sun will fix... ill try UP, but un-clamped in hot weather, but maybe it sounds like ill have to go to the trimmer and see if its either of these 2 problems?
Cheers for the help guys!