Sunroof seals

My son has a Lupo, it is getting on a bit and in need of some TLC, some bits we have sorted and some we still have to do, since buying the car it has been dry weather but now it is pouring with rain the sunroof seems to be leaking.

It is a manual glass pop up sunroof that sits on a rubber seal when closed.

Does anybody know how sit the glass lower on the seal or if the seal can be bought separately to replace the old one?

I am not sure of the make of the sunroof but it looks like this picture. Thanks for looking.