I sometimes take a train (to my younger daughter) who lives in Bedford.

As you may know there are 2 services from St Pancras to Bedford. A slow
one run by Thameslink and a fast one run by EMR

I go to the booking office and ask for an off peak day return and for
£15.70 get handed a ticket that states "From London Thameslink to
Bedford Valid via any permitted route"

I invariably take the fast EMR train

Sunday night when I came back (by EMR) my ticket was refused by the gate
and an official used his card to open the gate for me - giving me a
filthy look as he did.

As I say I just ask for a return at the booking office - do I do
anything wrong travelling by EMR when the ticket says "from London
Thameslink"?
--
Bryan Morris