Mine doesn’t leak , though just replacing the vinyl roof lining and headlining . The original was starting to crack at the rear edges. Did a trial fit today and all ok . Hope to have it completed soon . They come up on EBay regularly sometimes going for silly money , depends on condition, the size you want is 34” x 34” . If you want to pursue the idea let me know as I’m also restoring and fitting one for my son who has an MGB GT
Paul