Heres the latest: Cleaned most of the playfield with a light app of Goof off, was a bit scared to go too hard, then swapped to ME and IA again, cleaning regulaly as I went with a clean rag. Seems to be getting close now.
I reckon it definately had a clear coat that yellowed, it was actually applied over the mylar pieces as well.
Just about had enough of this crap, felt like throwing the whole thing out a few times.
My hat is off to you guys that do this all the time, you must have an extremely high patience level!
Lets hope it as all worth it in the end.