This rule is so illogical and, quite frankly, ridiculous (in most such
circumstances it makes using the Gold Card far more expensive than

I think it might be to penalise annual ticket holders who split their
ticket to save money (like I do). I have a season from Potters Bar to
Oakleigh Park and a Z1-4 oyster, which saves nearly £400 annually over a
normal "all zones and extension" ticket. Probably like most commuters I
rarely stray from my route and any social stuff I do is along that route
and only out as far as Z2 in any other direction. I probably do Z3-6 about
twice a year if that, which I can do on prepay using vouchers when delayed
on the tube

But of course, if I try to buy a discounted travelcard for the girlfriend,
I have to buy one for myself. I bought a couple but finally the ticket
office informed me this was not allowed.

The ODTC is £10 so it's more expensive to buy two discounted tickets than
one undiscounted ticket, so we just pay full price. I haven't tried
mirroring my ticket getting a discount CDR and full price Z1-4 but I don't
expect the ticket office could sell such a ticket as we're outside Z6. If
they did, this brings the ticket down to £7.40

I guess we only go into London 20 or so times a year so that 17% saving on
my normal ticket is the better option.

D