http://www.atocrailwarrants.org/the-season-ticket-rail-warrant-account
Pros
You have no worries about getting replacements as the person who got the ticket can sort it out (although you may need to write out warrants for some changeovers).
You get four to six weeks to pay up and you can compare the tickets issued on the warrant with the carbon copy of the warrant in the book.
Refunds go to the warrant account, not the person applying for the refund.
Cons
It costs money.
Thanks. I had no idea. THis would be very useful and I think we would probably cover the £500 or so a year in the saving on delivery currently. Only downside is I'll need to wait until the contract is up. Changing again this soon will not please some people...