"Andy" wrote

I don't think that platform 8 is regularly used by Southeastern
trains. It is accessed by from the Southern gateline and there is a
gate between it and platform 7. Physically, the pointwork allows all
of platforms 3-8 access to/from the 'Brighton' lines at Victoria
(rather than via Stewarts Lane), but I can't remember if the
signalling allows it.

IIRC platform 8 has its own gates, and can't be accessed through the gates
to any other platform. It has at least until quite recently been used by
Southeastern trains. Time was, of course, when it was a full length
platform, and regularly used by - and specifically labelled for - the Golden
Arrow.

Peter