Checking old and new parts lists, including pre 2005, and 2014 on, the inner control rod end has the same part number, MSR0600. The bolt is a MGB0560 1/2 by 2 1/4. This suggests that the bolt through the bush has always been a half inch bolt. My measurement of the i/d of the bush was 12.8mm. The differing o/d of the bush may have been down to a change of supplier.
