I think you are being rather harsh on the CAA. The UK Government in its pursuit of Brexit was never going to be "advised" by anybody who tried to explain to them the inevitable pitfalls of the path they were pursuing. Such advice was "Project Fear" and organisations that dared to speak truth unto power were at best sidelined and ignored. I suspect they hoped that at some point reason would prevail and the obvious insanity of leaving EASA would be avoided. The trouble is that logic holds no sway when political ideology takes hold.