Nah, there's loads of fairly rigorous indices about perceptions of different countries. e.g., the UK is perceived as having a very low level of public sector corruption
https://en.m.wikipedia.org/wiki/Corrupt ... ions_Index
And similarly there are surveys done of particular groups, such as asylum seekers, asking why they chose the UK (from memory, the leading factors were (a) not actually choosing, they just go where they can get trafficked easily, (b) language and (c) premiership football).
The case in the OP is clearly abhorrent, and the military has form for covering up misdeeds perpetrated by its employees be they against other employees or foreigners - they're even worse than the police in that regard.
But it's not clear to me to what extent it tells us about perceptions of the British generally, relative or absolute. There are loads of countries where people are in fear of their own police and military for doing stuff like this all the time.
The piece's more general points about lack of acknowledgement, consequences or reparations for the UK's ugly colonial legacy obviously stand, and it's thoroughly depressing that that kind of callousness continues today.
We have the right to a clean, healthy, sustainable environment.