A little routeing puzzle for you. Today I got the train from Wimbledon
to Staines. I looked it up on the planner yesterday and it gave me a
route via Clapham Junction for £3.50 (with YPR). When I got to Wimbledon
I was given (by the machine) a ticket marked NOT LONDON, for the same
price, £3.50. I had doubts but decided to go via Clapham anyway, as the
price was the same and the planner didn't mind. At Clapham I found an
SWT official and asked him about the ticket, thinking that I might not
be allowed this route, but he said it was fine.

Now, because of the Richmond loop there are indeed two routes to
Staines, one clockwise and one counter-clockwise (actually three if you
count via Weybridge, but I think it's forbidden). One would have thought
that 'not London' would force one to go clockwise round the loop. So who
was right? Logic or the official? And if the official was right, what
can be the purpose of disallowing London?

Thanks in advance for any answers.

Alex.