Interesting, possibly a large booked party from Oxford? to

Somebody in
FGW▸ might actually have made a decision to serve their passengers (shock horror) and put a special stop on a suitable train for the party given the known loading of other services stopping at Didcot or maybe it will save them a change.
Wonders will never cease, perhaps a one hand clap for FGW, if they could be that flexible all the time we may get a proper railway.