Rob/Tony Yes I think that is the solution but it is more sutle than one foot being higher than the other.Looking at the crankcase in the chassis both feet are the same height and the web is parallel to the chassis.So the main body of the crankcase is canted with the web staying in the same relative place.
I recall now when the TT was being assembled a standard crankcase was fitted loosely to check clearences and the starting handle was centre of the shell.When the Sports crankcase was fitted it was still centre .