I am not sure PB has any clout with Southern, but who knows.
Looking at the timetable as it currently appears, anyone arriving at Brighton station after 14:17 will have to wait for the 14:47 and just miss the kick-off or, if that's too full for them to get on, catch the 15:05 and miss the first...
The usual match day shuttles are just part of the normal Monday to Saturday timetable. It's been like that since May 2018. All Southern seem to do now is lengthen trains rather than run extra trains, even if the match is on a Sunday. I wouldn't be surprised if they have run 0 extra trains for...
"Enhanced" presumably means lengthened trains rather than additional trains in this instance, but you can scarcely blame people for thinking it means more trains. Chelsea all over again. FFS.
Incidentally, trains every 10 minutes on a Saturday has been the standard timetable for a year now.