"There is not much point in going to platform 14 because, as far as we can tell, no passenger train in service is ever scheduled to arrive or depart from this platform on a regular basis".
That statement is not true, there in the peaks a number of Didcot services booked there, it does come into its own when Elizbeth services are diverted into the main line station.
Indeed there is a arrival and departure pair of Didcot semis @ platform 14 around the time I am writing this (12:50 & 13:08) - at least accoring to
Realtime Trains.
Also stops at Platform 14 @ Reading.