In message

, at 15:34:00 on Tue, 4 Mar 2014, Recliner
remarked:
Same thing at KXSP between Thameslink and LU, yes?

Yes (in reference to just one fare being charged).

True, though I don't know why people would change there rather than at
Farringdon, apart from the lack of step-free access at the latter.

It would be a bit out of the way to go from Luton to (say) Victoria, via
Farringdon.
--
Roland Perry