I should imagine there are quite a few aircraft flying with Merlins that are not entirely appropriate to the Mark but what the hell!
I believe one of the two-seat MkIXs in the UK has a Packard so technically it should be a TR.XVI I guess.
I seem to remember that the BBMF's Griffon Spitfires have Shackleton engines with the contra-prop gearbox replaced.
Keep 'em flying!
