"The establishment of CAS should not in reality hamper other airspace users"
I agree it shouldn't but sadly it does. Look at the volume of airspace that is the Scottish TMA (inc EDI and GLA) and think how much of it is actually needed. Then think how aircraft that do not get clearance through have to take large detours you will see why CAS is a problem. Most pilots don't mind a known traffic environment but sadly they become a "no traffic environment" too often, as the above is. If one were to plot the actual tracks that are flown it would represent a small percentage of the volume of airspace. Airspace reserved for cross runways that are seldom used. Airspace down to the surface 10 or more miles from the airfield. Airspace below RVA. SIDs that reflect climb gradients of aeroplanes long since consigned to museums etc.
Is the reason for no radar at weekends due to the cost of staffing or the lack of staffing? If so It would be likely that non CAT would be refused entry to any CAS due controller work load/shortage ?