CRM is not in isolation a pass/fail subject as far as the caa are concerned. If the flight crew do fail in one area of there LPC ie single engine go around and it is believed that poor crm brought this about then they can fail the LPC and the fail can be attributed to CRM. Ie if you had two pilots who got in the sim, didn't say a word to each other apart from sop's and were seen to pass all the usual technical aspect of an LPC then they could not be failed on CRM (that's the easiest way of thinking about it).