With modern aircraft performing better than they did years ago, what would be the point of lowering the base of CAS from FL55 to 2500 feet? No sensible ATCO or pilot is going to want to have jets flogging around at 2500 feet over the south coast.
As someone who works on both sides of the fence, I do however fear the possibility of charging for ATC service for A/C under 2000kgs. But if this charge were to be at a reasonable level, say a one-off charge per flight such as a landing fee, then would most sensible people object? After all you are getting a service, and how many of those are free these days?
The point is it has to be at a sensible level, not like it is now with Eurocontrol charges which are higher than the cost of the fuel for the trip.
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"Take-off is optional, Landing is mandatory"