On Mon, 12 Mar 2007 13:53:46 +1100, peter wrote:

I will be travelling from London (Kings Cross Thames link) (KCM) to Brighton
on a Saver return (£24). (I am aware of the alternatives via London
Victoria, but will be arriving at Kings Cross from the North so thought that
would be easier.) I will be returning to London a couple of days later, but
need to get to Waterloo (to catch the Eurostar). My question is will my
return ticket to (KCM) allow me to alight at London Bridge (LBG) to catch a
train to Waterloo East (WAE).

Yes. According to the NR Routeing Guide, a valid route for the ticket
is Brighton - London Bridge (via Forest Hill) - Waterloo East -
Waterloo - Clapham Junction - Streatham Common - Tulse Hill - Herne
Hill - Blackfriars - KXTL (good luck getting that past a ticket
inspector, though!), so you're entitled to use this route and abandon
your journey at Waterloo.

Another valid route for the ticket is Brighton - Clapham Junction -
Waterloo - Waterloo East - London Bridge - KXTL, so you could also use
this route as far as Waterloo.

(All of the above assumes the ticket is marked "Not Underground",
rather than "FCC Only" or similar.)