I'm curious as to why so many stations have had the county name added. It makes sense if there is a town / village of the same name elsewhere in the UK▸ but I can only find one Epsom on Google Maps and Bing Maps so why rename to Epsom (Surrey). Is it anything to do with Oystercard acceptance?
There is a West Drayton in London, another in Notts, so why did West Drayton station not get renamed?
In a lot of cases it's about confusibility, so not identicality. For example:
CEL renamed from Chelford to Chelford (Cheshire)
SED renamed from Shelford to Shelford (Cambs)
SFR renamed from Shalford to Shalford (Surrey)
Where all places have stations that's clear enough, as all are in the list. Where one place has no station then in some cases they appear to have lost their county qualifier (presumably the station was lost ages ago). However, in some cases I think another town may be considered a possible confusible where it's big enough someone might think they can get a ticket to there.
That makes it all a guessing game - what did the naming people (is that Network Rail's job?) think the public might think it might be? All very open-ended and subjective - rather like the only exam I ever failed outright: a Use of English paper. We were given some badly worded sentences supposed to be by other candidates and asked what was meant. That meant guessing what examiners thought teenagers would have meant if they wrote them, but we knew what we would have meant and that was not the always same. There was a big complaint from schools and it was reset and resat.