I am not suggesting that mode S data should not be used to improve situational awareness at all. In fact I am saying that the information missing from mode S, e.g. the unit providing the service, should and could be added by simply using a unit specific code. You will still retain the mode S data and all other units will be aware of who is providing the aircraft with a service. You may have the luxury of mode S, but is this true of all of your neighbouring units? I know that we do not have mode S, nor do several other adjacent units. All we see is the squawk, level and, if required, speed of the aircraft.
As for the examples in your second para, I'm sorry but you do not "know" which unit is providing the service. You may be able to make a fairly accurate assumption based upon previous knowledge and experience, but this is not the same as knowing.
ORCAM squawks appear from all types of minor aerodromes with traffic flying VFR but looking to join CAS
In this case how do you know if/when the squawk has been validated and verified?
I'm afraid you are wrong here. A 7000 squawk is unvalidated and unverified and requires greater separation standards than an ORCAM squawk which is validated and verified.
Really? As stated above, can it be guaranteed that the ORCAM code has been validated and verified? With a discrete unit code this is a requirement.
Also;
MATS Pt1 Para 10A.5
Aircraft Under Deconfliction Service
. If the intentions of the Mode C transponding aircraft are not known, the vertical deconfliction minima must be increased to 3000 ft, and unless the SSR Mode 3A indicates that the Mode C data has been verified, the surveillance returns, however presented, should not merge.
Are these not the same minima that are applied to aircraft on a 7000 squawk? Which is why I say that in class G airspace an ORCAM code is no better than a 7000 squawk.
Although we do not have mode S at work, I can see it can be a very useful tool, with all the extra information available. But I also feel that being able to identify, without any ambiguity, which unit is providing a service quickly and easily is important. ORCAM/CCAMS codes do not provide this, mode S or not.