Seems to me the problem with VFR CAS transits is the inconsistency. Last week a PPL I was flying with made an ambiguous call to ATC in an adjacent zone which we intended to route around. The controller took it as a request for a CAS transit and immediately gave us a transit clearance direct to our next turning point, at our current altitude! OK, probably no traffic to conflict, but it was a refreshing attitude. Others will be the opposite - "Flight Information Service, remain outside controlled airspace, report leaving the frequency" - yeah and cheers to you too mate.
I would imagine the best source of consistent standards on this and other ATC issues ought to be the CAA regional ATS inspectors. Over to you Mr Regulator?
NS