The CAA do know the causes of all of these accidents as they are looked into in quite some depth by the AAIB. The accident reports are available for anyone to read online.
The CAA is being forced to make a change by the Unions (who really have no clue about the aviation industry) and realistically there is no changes to be made that will really make any significant difference as far as safety is concerned. So they took the step of looking at a variable that does affect the likelyhood of escape - the size of the workforce! (And quite right too).
Its now quite amusing that the Unions, who are set up to protect the interests of the workforce, are now potentially putting their workforce directly in the firing line should a size restriction be enforced.
So you are correct Tomcat - I think this is a shrewd move by the CAA, just an action to calm them down a bit.
Maybe in future the Unions should keep their heads down and mouths shut instead of trying to judge the aviation industry by its own standards.