BAA
As far as I am concerned there is a major factor involved. LHR is run by BAA = Bureau Against Aviation, an outfit which likes to have shopping malls with a runway attached. Its management have very little experience / knowlege of aviation !
I am talking as someone who used to work with them.
I know of an excellent Ops Manager with excellent experience. When he applied for Ops job at BAA was told "you will have to work in security and after 2 years apply for Ops".
I know of a woman who speaks five languages, and who applied for a vacancy at Airport Information Desk - she didn't even get a reply !
Look at the improvements made, and being made at LGW since BAA sold the airport off.
BAA = Bureau Against Aviation