I don't have a 16mm drill bit or a vice or the ability to assemble the units with springs to check the fitment myself after modifying. It's booked into the garage for Monday to get the dampers fitted so I don't intend to muck about with something that was never a problem, I just wanted fresh parts while the dampers were getting changed and didn't think they'd be so unfit for purpose out the box.
When you say original top covers with nuts...are they one piece items with an integrated nut?
Affirmative.
I would guess the garage has a vice and a drill bit though,