Bank Holiday timing overlapping with normal Tuesday weekday timing, possibly?

Almost there. After chatting to the guard on my Southern train, it would appear that
FGW▸ are operating a Saturday service whilst Southern are operating a Sunday service. Apparently there have been quite a few clashes here and there today.
Just another example of how a fragmented railway can cause confusion for customers. I just assumed all
TOCs▸ were running an amended Sunday service today.