Andu:
This thread is all about the use or the misuse of 121.5 in the United Kingdom. It is not about the use of 121.5 at Bushire, Shiraz, Esfahan, Bandar Abbas or Ras al Khaima.
So, you tell us that you fly around the hold at Lambourne and down finals at Heathrow with 121.5 turned fully up just because the US Navy shot down an A300 years ago in the Arabian Gulf (which I do admit is close to Essex) and all of this because your SOPs say so.
Well then, I think your SOPs or your understanding of them is sadly lacking.
As a TRI/TRE I thought I had better make sure that I hadn't forgotten what MY SOPs say so I looked them up.
The only reference made to monitoring 121.5 appears in the Part B/2.5.2:
2.5.2 En-route
"During longer sectors, in cruise, if no other communication is required, crews should monitor Frequency 121.5 on Box 2."
There is absolutely no mention of monitoring 121.5 during any other phase of flight except for cruise.
Perhaps you would be so kind as to tell us EXACTLY what your SOPs state?