The Jersey sidings were added in 1938/9and are the only ones now available.
A single Jubilee Siding remains available for use, but it’s a very far cry from what used to be there, as shown in the track diagram you posted.
The relatively recent addition of sleepers across the London ends of the two remaining Jersey Sidings prevents their use for run-round moves these days. I’m unsure whether Network Rail would make special arrangements for them to be removed if a train operator did require to use this facility.
As an aside, going back to the
OP▸ , the headcode for this train was 1Z65, 155R being the obfuscated version displayed on RealTimeTrains, Traksy, etc.