Thank you. It has two sloping panels and then the vertical. The leaks are at the lower edge of the higher panels.
I'll try the one you suggest - I shall have to do it on the inside as access to the outside is impossible without taking out glass panels.

I have a Hartley 7 leanto greenhouse which has been very good and still is in good condition but the roof panels leak at the bottom edge. This started about two years ago and has got worse. As far as I can see the PVC sealing strips on the glass edges have perished. Apart from reroofing with new str...