In article ,
"Graham J" wrote:

Customer services is permanently engaged or busy and I can't find the
information on their website.

It would be nice if it were first hand information on their website but
failing that http://www.nationalrail.co.uk/tocs/thameslink.htm#6 ought to be
reliable information.

I had seen that, and noted that it talked about 'trains that arrived in
London', but didn't necessarily talk about going through London! The
consensus seems to be that it will be ok though - thank you to everyone
for their help.

James