David Biddulph groups [at] biddulph.org.uk wrote

Railist wrote:
I want to use my SouthWest Trains Gold Service ticket on a Friday
afternoon. (This is the free weekend travel one).

T&C includes "This ticket is not valid for travel from London
Waterloo
or Clapham Junction on trains departing between 1600 and 1900
inclusive on Fridays".

I want to travel get the 1620 to Exeter Central from Waterloo.

Is the interpretation of the T&C that I can't travel using the
ticket
from Waterloo, but I could buy a ticket to Woking, then use my Gold
Pass from there? Or is it any train that starts from Waterloo/CLJ
between those times, no matter where on SWT I join?

"...is not valid for travel from London Waterloo or Clapham Junction
..."
sounds clear to me.
It doesn't say "... is not valid for travel on trains departing from
London
Waterloo or Clapham Junction between 1600 and 1900 ...".

And, if you can leave a little earlier, you could save buying a
additional ticket to Woking by taking the 1553 to Woking and picking up
the Exeter train there.

And if your query had been for the 1720 or 1820 an additional option is
to buy a ticket to Vauxhall and take a stopping train from Waterloo to
Woking.

--
Mike D