The two bottom half's on the left don't have the timing cover with the circular boss and BSA marking, wouldn't that make them JM24's, and is there some reshaping under the KM24 engine number?
The barrel in your photo is from a 1938 M24, identifiable by the 'two screw' tappet cover. 1939 models had a 4 screw cover...The pictures below are of the 1939 ISDT team...The first taken at the docks in the UK, the second at the hotel in Austria where the team stayed...EOG22 has had more markings applied between the two photos...I have the original photo of the second image...Ian