Damaged marine ply

[themannsindorse]

P { margin-bottom: 0.21cm; } I have a 20' cabin cruiser (see picture) with a GRP hull and marine ply top. I purchased her two years ago and the time has come to re varnish her. One problem I have is a previous owner (I am the third owner) used a power sander and accidentally went right through the top layer of ply one of the side panels. He or she did notice notice this at first and quite a bit of damage was done.
This has left depressions and also a lighter golden colour. My first thought was to just strip the varnish off, stain the light coloured bits to match the undamaged bits and then revarnish. However it would be nice if I could somehow re veneer the entire section or possibly “fill” the patches so that it all becomes flat again.
Has anyone out there had to tackle this kind of problem and do you have any tips for me?
Thanks. Peter. Dorset. UK.