Avro was pitching the Arrow to the UK in a bit of desperation, I think, but the interest from the RAF was said to be quite high, especially given the familial linkage of Avro Canada to the original Avro. WWII was only still recent, and Avro Canada had joined in Lancaster bomber production back then, so there were optimistic visions of British sales.
You mentioned the TSR-2's role as a low-level nuclear interdictor - this same role was taken up by RCAF CF-104 Starfighters(!) stationed in Germany carrying U.S. made free fall nuclear bombs on planned routes into Poland and further.
Hrm. The german F-104G were planned for the same 'drop that thing high, and get the hell away from there!'
Meaning when reaching the target, leaving low-level flight, and letting the eggs fall while curving up, so the eggs 'fly' for a while in a parabolic arc, longer than actual free fall. So plane and pilot would have (more) time to escape the blast.
Was described in much detail in the 'Reibert' for the Luftwaffe from the 80ies.
You mentioned the TSR-2's role as a low-level nuclear interdictor - this same role was taken up by RCAF CF-104 Starfighters(!) stationed in Germany carrying U.S. made free fall nuclear bombs on planned routes into Poland and further.