"Mizter T" wrote

But you make a very good point about what might happen to the
Blackfriars (and soon to be Kentish Town) to Sevenoaks services -
they'll be approaching on the wrong tracks to use the bay platform
(they could presumably get in there but they'd block the everything up
by so doing). So it seems possible that this Sevenoaks service might
permanently turn into a Thameslink service from December onwards -
which is exactly what happened in the early years of Thameslink. If
that does turn out to be the case it would be welcomed by many
passengers.

It's too early to be sure of service patterns when the all-singing
all-dancing Thameslink eventually happens. But current thinking is that the
new Blackfriars bays on the west (upstream) side of the layout will enable
Southeastern trains via Denmark Hill to terminate without conflicting with
Thameslink trains via London Bridge. They will of course conflict with
Thameslink trains via Herne Hill, but the idea is to upgrade crossovers on
the London side of Elephant so that Southeastern and Thameslink trains will
swap tracks there. With 6 Thameslink tph (in the peaks) via Herne Hill (18
via London Bridge) and 4 Southeastern Catford Loop plus a couple of fasts
(Gillingham or Maidstone) this should not be too difficult.

Peter