Hi Tony. Yeah I ended up deciding to modify a MaxLiner 5 piece under rail liner. This made it easier to modify.
I’ve uploaded some photos. It was a very intricate process - I made small cuts to ensure I did t take out too much. The corners were this biggest hassle as you had to cut out a bit of the end and side piece which was very hard to judge.
It was imperative to remove the bars - and this was not a pleasant process.
Also had to install the pieces in the opposite way. Ie the base was last to go in - so it was much more fiddler.
min the end I am absolutely overjoyed at the result - I just never want to do it again! Next will be to draw up a custom checker plate storage box.