Rear reg light holder - part number?

[nugget]

guys, an unusual request, looking to replace one of the rear registration plate light holders (not the bulb....that would be too easy! but the whole perspex lamp thing) on a Mark 1 Tuscan, any idea on the part number to help locate a replacement.

Or failing that, is it an universal part, off a Ford or the like? Any replies would be gratefully received, cheers!

p.s. the more observant amongst you will realise that there are 2 of these, so why not just get the part number off the other one I hear you ask? well....tried that but to no avail, appears totally unmarked!