You are wrong about this, class 2 trains on the North Downs Line do not have first class on them, this is shown in the advanced pathing information on Real Time Trains, but is also GWR policy now (and I believe it has been so since at least December)
And as previously said up thread, many of the class 2 work on the north downs are still operated by first class fitted 166s, for reasons again posted above.
As for GWR policy, what do you mean? As in advertising Class 2s as not conveying First Class? The reasons for that were in the post you've part-quoted.
RTT, again, is only a digital presentation of exactly the same data used to compile the paper timetable, or power NRE booking engine etc etc. If someone wants to provide some actual documentary evidence that categorically says First is
automatically declassified if not advertised, I'll back down. Until then no other stance is defensible. Yes, most sensible guards won't Quibble over it on a route that doesn't regularly have First Class, and won't challenge people over it, but it isn't an automatic carte Blanche declassification if not advertised. As per CoC G 39 standard class ticket holders may only use first class accommodation with the permission of a duly authorised person - so my original point stands - the guard was within his grounds to evict the schoolboys referred to.
I don't want to take this thread off topic further - if anyone does actually come up with something concrete that does authorise standard class ticket holders to use first class when trains are advertised as standard only, I'd be very interested to hear from you by PM. Have looked into the subject extensively in the past, I can only wish you the best of luck.
To drag things back to the topic at hand:
Greenford services will also always produce a 2car 165, as will 2E90/2E92 Oxford - Worcester. These are down to short platforms and no SDO on turbos.