GWR was also affected by flooding near Woodborough affecting all services to the West of England. What didn’t help was unrelated to the weather several incidences of a complete lack of signalling in the Swindon area.
Mother-in-law caught up in that on way back from Cormwall - held at Westbury for a while, but eventually diverted via Melksham. "Only" about 75 minutes late (which seems pretty good compared to the rest of the network today)
Hundreds, no, but some? Any at all?
Good luck dealing with far more passengers than a few buses could actually carry. I mean hundreds and hundreds of passengers outside station that could not fit on a couple of buses