You can see where I started to cut and in the end I made several cuts and then pinned it all back together to get it aligned..
This picture shows that either side is now the right distance and even the windscreen mounting is looking aligned.
I did do plenty of measuring and checking before I cut and I think where the side piece was bonded together, it was just put slightly forward. No big deal, just a day of pondering, cutting, and sticking back together.
I am expecting some adjustment of the bonnet now, but, hey, that's the fun of these cars!!