Oh, what a complicated web we weave.
The basic question was to identify the Mks and point out the
visual differences.
The under-fuselage aerial was not mentioned by anyone.
Most mentioned the different engines, though some got that info. from specifications rather than the photos.
I've given the benefit of the doubt to anyone who mentioned that difference, despite a comment that they weren't evident in the photos.
Some added correct notes about changes in the early marks regarding undercarriage and tailplane, but they weren't different between the depicted Mks. Waist guns also got a mention, but again, both Mks were similarly equipped.
The second part about the deleted feature was only mentioned by two, so well done to the diamond recipients,
AllanL and Pete (MilesMan)
That feature was the ventral turret of the MkI, which was certainly gone by the time the MkIC was produced.
Scoring gold for identifying KXoM as a MkIC, and EPoR a MkII, and mentioning the Merlins vs Pegasus, were:
Mick (woody901) and Christopher Storey.
Silver goes to Pete (Motormouse) who identified KXoM as a MkIII. The book says that in the air, the MkIC is indistinguishable from the MkIII. Pete had other information, which showed that he wasn't just doing a quick google. Pete didn't include the engines.
EDIT Also silver to Den (511Flyer), who disagreed with the MkII, but did mention the engines.
Here's the full page showing EPoR, with some interesting points.
The sequence of codes on EPoS
The painting of codes and roundels over the waist gunner's windows in 3 of the 4
I see that the same had been done on the photos of the MkIC as well.
All in all, it was a revealing excercise, and I thank you for your participation.