Case closed unless I am totally wrong.
I wouldn't say totally
but you are wrong.
Please go back to Paul's original reply, above, take the link he has provided and do not "move about" in Google Street view.
You are correct that the old, legacy, cast-iron GPO PCP has been replaced with a modern pressed-steel shell but that is not an "all-in-one" cabinet. Look across Warwick Road to the opposite pavement and there you will see the "fibre twin" to PCP number one.
100% Linux and, previously, Unix.