Sails on eBay (short main foot, tall jib)
The ad seems to suggest that there's no kevlar/ carbon weave in the sailcloth - just mylar laminate so presumably capable of stretch in higher windspeeds - unless it's advertised inacurately.
Hard to tell, but there were/are some Mylar cloths with a very lightweight mylar scrim. Could be what these are made of.
Mylar sails were about in the 80's, I had some on my old boat, they worked quite well but could eventually delaminate
These look like they are monofilm, with some reinforcing tapes out of the corners and head-to-clew on the main. They will have been made by either UK Cork, UK Hamble or UK Cowes, probably approximately ten years ago. These lofts were all big-boat lofts, with very limited dinghy sailmaking knowledge. The sails were likely made by someone who worked at one of these lofts, for their own boat or a friend's boat, and will have been a one-off. The blue nylon soft foot on the main and the light blue dacron tape on the luff were features of UK Cork and Cowes sails. The monofilm should be physically strong enough for most wind strengths, but will crease badly and subsequently rip if not looked after.