Clearly The Starter you have is not for the AC Weller Engine, however i developed the AC Weller starter in conjunction with WOSP in about 2005/6, they were able to supply a 2 kilowatt Denso Pre Engaged starter body & an extended shaft & 11 tooth gear & i designed & made the prototype which was fitted to one on my new engines fitted to a Frazer Nash, which is still working well today!
WOSP then used this information to reproduce them whilst i continued to make my own!
I believe the 2 kilowatt starters are now replaced with the 1.4 Kilowatt units for the AC engines.
Robin