Peaky my man, some questions.
I've come to fit the undertray today and it seems miles too wide, the shell no where near fits and it doesn't look like the picture you posted. Not sure which bit needs trimming and how it will make any difference to the width.
It's also close the the motor i assume i need to remove that?
The old under tray was attached with with 2 screws right at the front, then w more underneath at the front then 4 at the back, the screws don't look original i assume it's best to just stick em back in?
Some pics below will hopefully show what i mean