@andrew-benn, assuming you've been pleased with your Gunned 1.6s I'd suggest you have two options. But that $1.7 to 2.6K repair from Magnepan is not one of them.
First, you say "what seems to be splits in the mylar". That is not definitive but should be verified by visual inspection. That should be easy since PG didn't cover the back of the panels. If the mylar is good and you only have the dreaded wire delamination, repairing that is your answer.
If the mylar has in fact split I'm not aware of any repair for that, so replacement would be your only choice. I don't know how easy to find but it would be much cheaper to buy another pair of undamaged 1.6s and replace the panels into your frames and with your crossovers..
If not prepared to do that work yourself then simply replacing the entire speaker system seems best. I like bdp24's suggestion for an ET model.
I would also suggest going to PG's website (still up I believe) and reread his comments on newer Maggie models. I understand they are loved by many people, but the PG mods are a different direction so if you loved those consider the newer models may sound quite different.