Benson; not open much at the moment and likely to be less so in the future.
Brize; LARS hours much less than TK opening and they don't want to provide a service to IFR traffic at TK.
Farnborough; Doesn't reach that far.
The people at TK are not fools and wil look at every option on merit. Radar the sooner the better for the operators.
TK