Positive identification of almost any but the earliest Churchill tanks is both a fraught and intricate process.
That there were so very many of the vehicles mongrelised has a lot to do with the difficulties in a positive identification.
There were welded turrets with extra plates welded over the original, there were cast turrets with extra plates welded over the original, there were cupolas added that had not previously been fitted at the factory, there were suspension components changed in both model and position of mounting, there were differences in gun mounts and hull gun mounts, between any two vehicles which had been produced side by side in the factory, etc etc.
All of this, without even making mention of the comparatively large numbers of “factory mongrels” which were produced as expediency at various times.
In fact, it is reasonable to say that for the British, the Churchill tank was every bit as mongrelised as the Sherman was for the Americans, and for much the same reasons, with the possible exception of engine issues in re: the Sherman.
Kind and Respectful Regards Leccy, Uyraell.