[Aussie Mike]

The mounting holes on most number plates are common distances apart. You'll see most plates have a range of holes accross the top and bottom to take into account different mouting systems but they usually follow the same pattern even on different width plates.

I did the nutserts into the boot lid and then spaced the plate off the paint work with some nylon washers. I'm fairly confident I could unbolt my slimline 5character plate and put a full size 6 character plate with the same bolts.

Cheers