130 crew cab roof split Help

Hi all, I have a 98 Defender 130 twin cab (ex SSE Electric truck) and the seam/join in the centre of the roof has separated.
I was after some of your hard earned experience please.
At the moment it is kept watertight with good old duck tape, but it appears as if the spot welds have failed and the seam has opened up.
Has anyone had this problem before and if so how did you deal with it?
I have been told to just rivet the seam and then seal the rivet holes...is this a good idea?
What other options are open to me ?

All comments and ideas welcome.

Cheers
TBP

tig weld, re spot, rivet and tiger seal, new roof

Gripfill

I know you can buy rivets with closed ends. These will not let water trough.

Of you clean the seam really well, drill some holes where the spotwelds were, put a decent caulking on the seam. Press it toghether and rivet shut.

You can choose to put some caulking under the lips of the rivets.

Should seal it up...