Kensington Olympia was also used for WCML diversions in the 1960s (and became London's Motorail terminal).
Kensington Olympia was my local station in the summer of 1983, and it was interesting. My family was abroad so I had no reason to go home for the holiday and instead rented cheap accommodation from Imperial College in the vicinity. Plus a job as a contract computer operator in West Croydon.
Two really long platforms on passing loops which were hardly used at all, the relics of the motorail infrastructure I'm sure included a couple of bays too.
There were a few passenger trains going through each day by then, but they didn't call at Olympia.
There was a morning and afternoon shuttle to/from Clapham Junction booked for 33+4-TC but could produce 73+4-TC or even stranger things. I used these when my shift matched, otherwise I went to work by bus, train from Victoria or train from Holborn Viaduct for the variety (the latter because the Central line from Shepherd's Bush was an easy change).
There was a booking office but I can't remember what hours it was open, but even when it was I don't expect it got much passing trade - I'd expect most of the passengers had season tickets anyway.
In 1983 it wasn't really in a "desirable" part of London, although it was close to those that were. I lived almost in Shepherd's Bush which certainly wasn't.
Funny for me to see it these days .... things change!