The TFR was a UOR buy in from General Dynamics from the F111 programme. The narrow look angle was necessary for the F111 to avoid it being given unnecessary flyup commands if it flew down a valley.
I am not sure about provision for the TSR2. It navigation radar was a side-scan system which would be used to update the nav-attack system after the fix point had been passed. I suspect that terrain avoidance was planned on a mission basis and not a dynamic process. Given that it was planned for weapons release down at 50 feet and mach 1.2 you would have thought it would have needed some form of forward looking system - FLIR based perhaps?