Great Western Coffee Shop

Have you noticed how often London expresses at their outer destination seem to creap in to a platform at the far side of the station as if they're apologetic for being there? I've noticed it many times at Bristol Temple Meads, saw something similar at Sheffield last week, and I've just realised it's the same at Hereford.

In the case of Bristol, it's because the route to London swings East almost immediately on leaving, so they are minimising the number of lines HSTs need to cross in order to turn 'right'

I do think it depends on location.
Sheffield - most use platform 5, in the middle of the station and handy for connecting trains. Also being in the middle it is the same distance from the station front (walking, taxis and bus station) as it is from the tram stop at the southern side of the station.
Leeds - East Coast's trains use platforms 6 and 8 ( actually adjacent) and these are the closest to the barriers.

Mostly it is to do with operational convenience, which is why Cross Country services from Bristol TM leave from near to the barrier and fGW leave from the far side (as explained).

I reckon an 'InterCity' type TOC would prefer not to annoy its passengers, especially First Class, which is why they all still follow BR's InterCity rule of placing First Class at the London end of the train, and why they try to arrange departures from the same platform all day.