HD : Assumptions are one of aviations worst enemies. Ironically, it was my last visit to LHR a few months ago which raised this issue again - your ATC (ex?) colleague asked me a question which I would have expected him to have known the answer
The problem is that the Jepps all refer to CATEGORY not TYPE e.g. do this if you are Category A,B and do something else if you are Category C,D etc. How does ATC issue an intruction, e.g. a SID, if an aircraft reports a TYPE on first contact when the SID's are assigned based on CATEGORY