too many "old boys club" / funny handshakes around for that to be a risk.
Well, maybe; it was certainly a factor a decade or two ago and for all I know still is.
But the most likely reason in 2016 is the mixture of aeronautical incompetence, bureaucracy, and time-serving laziness that has taken over at the UK CAA, where anyone who might have had the balls to confront and face down the operational management of a major operator on a safety issue left the building a long time ago.