I've just had an interesting time trying to use the return portion of an Off Peak Oxford - Ely ticket. I'd used the outward portion, and Ely - Cambridge on the day of purchase three weeks ago. I then travelled by other means, but was in London earlier today and used the ticket to travel from Marylebone to Oxford. At Marylebone the ticket didn't work the barrier, but I was allowed through. At Oxford, they went and printed the journey history, but eventually let me through with some confusion about whether a break of journey was allowed. I thought it was. But am I supposed to have done Cambridge to London too in order to make the ticket valid for London to Oxford? I wondered if that's why it didn't work in the barriers, though it's not the issue the gateline staff brought up. (The stated reason for the query was that they didn't realise a break of journey could extend for a few weeks).