Zones have recently been added at Oxford, although this is the first time I have seen them in use.
Although they seem like overkill for a 2 car 165.
What is the point of the carriage letters and why E and D?
Notice the error as this service is standard class only and more than likely the train doesn't have any 1st class seating.
For when the trains are used as 5 cars on the Cardiff - Portsmouth service, the three car units are A-B-C and the 2 cars are D-E.
We are getting used to announcements about First Class on TransWilts trains too. And while at places like Chippenham it might feel like overkill, it does at least help people to know where on the 10 car platform the 2 carriages will be stopped.