Quite so - and the "line on the map" would, I am sure, encourage many VFR pilots to announce their presence anyway (as per a MATZ), even if they were not obliged to legally, in addition to the basic provision of compulsory separation of IFR flights, a fairly reasonable requirement.
The point is that the "active" area around an aerodrome in Class G airspace is not self-evident from the charts. The CAA put the stupid little "feather" on the chart to indicate the final approach to the main instrument runway, but the extent of the final approach is not indicated, neither is any other instrument runway, the reciprocal (for departures) is not emphasised (just as important), the area utilised for the procedural IAPs, the radar vectoring area or the holding pattern(s).
And the CAA is responsible for overseeing flight safety? Nothing will persuade me that it is not irresponsible. ICAO implies that an instrument approach really should be provided will appropriate controlled airspace and the pilot flying such an approach deserves nothing less.
If only all the ATC authorites at Exeter, Filton, Shoreham, Manston, Gloucester, Norwich, Southend etc etc would get off their backsides and get together and make an enormous stink about it ....! If CAA continues with its insistence on a minimum number of IFR movements and passengers (logic?) before establishing CAS, they are doing aviation safetya considerable disservice.