jimbo99 wrote:
I wish to buy a return from East Croydon to St Albans. I'll go direct
with FCC, but on return I'd like to get out at Farringdon before
continuing to East Croydon. Any ideas how to achieve this in the most
cost-effective way?

Assuming I'm not permitted to break the journey...

From what you have said (assuming you are on an 'anytime' or 'offpeak' day
return) you are definitely allowed to break your journey. However whether
at an LU or NR station you should not expect your ticket to work the
barriers mid journey, so you will need to approach a staff member to be let
out, and back in later.

Paul S