Bluenose - you make some interesting points - it is a shame you can't do it without the snidey tone of thinly disguised personal insults - I am not sure what scenarios you think I chose to ignore, perhaps you could clarify.
I have no doubt that you made a significantly greater contribution the UKSAR than me - I just wonder why you felt you had to say that - I'm just a driver/arframes who goes where he is told but if you think it is straightforward and less challenging than being in a warm, comfy ops room then come out on a dark and stormy night and have a go.
Despite your two scenarios, the only reason I believe that ARCCK would withdraw an asset from a search managed by MRCC is if they had higher priority tasking for it - they don't look over the shoulder of MRCC to see if they are doing their job properly.
Unfortunately, MCA are often slaves to SARIS when sorting out searches and, whilst I understand they are the ones who would go to the coroners court to explain why a search was called off too early, the guys on scene who are actually doing the searching are usually the best arbitrators of how effective the search is and whether calling off the search is a good idea or not.
If the system is complicated for the controllers (and I'm sure it isn't from those I talk to), whose fault is it? The RAFs for having the majority stake in UKSAR aviation?
The interim contract has at least proved that the MCA shouldn't listen to their contractors regarding perceived and actual capability of aircraft - still no overwater night winching in the Channel and it took over 6 months to give the S-92 the range to match the press releases.
Putting an aircraft into service without it being fully compatible with existing comms capability is crass and arrogant - hiding behind the idea that you are introducing new technology is worse and highlights some of the politics that go on far above our (or certainly my) payscales.
You implied the fault of comms problems was with the ARCCK - is it not the fact that you let you contractor specify sat tracking without HF without challenging the decision?