Following on from the above post, an observation I hadn't appreciated before today, is the difference in shape at the bottom of these original pillar post covers between passenger and driver sides. See 2 additional pictures below. Reproductions seem to be mirrored exactly from left to right, perhaps one of the reasons they don't fit like the General made them?
Fearing somehow I'd managed to buy a mis-matched set (as there are differences between '67, '68 and '69, as well as coupe versus convertible!), I had to go and check the originals still fitted on the car, and to my relief, those have the same differences as the spare set. Phew!