Thanks again for everyone who has taken the time to contribute, it's interesting for me to read the range of opinions and gain a better understanding of the rules.
I drove in yesterday (boo), so wasn't able to take photographs. Unfortunately today, the First Class Carriage was moved to the "wrong" end of the train, i.e. it was counter-productive for me to make my way there as I would then have been positioned very far away from the platform and would have to fight through the throng to get to the ticket barriers.
So consequently, this morning I still stood effectively where I would have been, albeit the locomotive was connected to a standard class carriage instead of a first class carriage. As such I could not obtain any useful photos of first class stickers, signs, or a lack thereof, so I'll try and do that on Thursday.
In the meantime, however, if this assists, this is where I would ordinarily be stood ("x" marks the spot), irrespective of whether the connected carriage was standard class or first class. I will be the first to accept that I definitely do not know the rules, however to my simple brain, I am not in the first class carriage at all. I have stepped off of the carriage, and am physically standing (as far as I can tell) on part of the locomotive.
So how could I be deemed to be "remaining" in first class, when I have physically left the first class carriage?
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