I did hear this ST, thanks for confiming it.
The advantage of having the Gazelle around, as some form of cover or indeed early warning, was that as they were basically of airfix form, the were not able to be picked up on RADAR.
This became a bit of a problem for 'peacetime' flying and especially when not in the BAOR Theatre for civilian controllers. This problem was overcome, again with British ingenuity, by issueing the crews with a radar reflective device.
Cunningly, this was disguised as an 'Aircrew Survival Knife' which allowed the Gazelle to show up on a RADAR screen, yet could also quickly be discarded when the Soviet hordes bolted westwards and stealth was once more the order of the day.
That is why;
1. Gazelle crews carry a 'survival knife on their flying suit.
2. The 'Survival Knife' couldn't even assist survival in the grocery department of Marktkauf.