I've now done some digging.
1. I have the 79-80 WTT (I had forgotten, I think I liberated it from work!) which is essentially the same as 83-84. There are no workings that reverse at Barnehurst - anything that started or terminated ran ECS via Slade Green or via the Crayford Spur (mornings to form Up trains only - a look at the map will explain why!).
So that answers for the OP's period.
2. However, prior to that there were trains that reversed Barnehurst in the morning peak - there are 2 in my 71-72 WTT. None in the evening peak as it would have blocked the down line for too long, and in any case it was normally easier to send them the longer way round via Slade Green. I also have a couple of early 60s Carriage Working Notices which show trains standing long enough to have reversed, but without the WTT I can't confirm.
So in response to
John Webb either the conductor rail layout was acceptable (the issue would have been the ramped ends not the gap) or alterations were made post 1954.
A look at the signal box diagrams for Crayford Spur A and B, which are on the Signalling Record Society’s website, albeit at low resolution, suggests that point locks were fitted on all facing points. Presuming, as is highly likely, that this situation was continued when the boxes were abolished in 1970, then there would have been no problem about passenger trains using the curve.
There were booked passenger workings Barnehurst - Slade Green - London, not just ECS workings, in both directions in my 1980s WTT.
These had run since steam days - unlike the Crayford Spur which was built in WW2 and signalled for passenger but not regularly used as such until relatively recently - I certainly "did" the Spur on a diversion in the 70s.