2) If I move during the year and I want to extend or restrict the
zonal validity of my ticket, what are the costs involved?

Cost is £5 admin fee for the change in number of zones, plus the pro-
rata cost (or refund for less zones) for the difference in the
validity. Plus the hassle of filling in the form and hoping that it
doesn't get lost in the post (which is what happened to me). The form
is available from any staffed station, but not all the staff seem to
know what it is. You also need a least a month's validity left to
exchange the ticket.

That's the kind of thing I'd always post using recorded delivery, it
only costs 70p. Of course it also costs the time and effort of going
to a Post Office - though it's worth keeping a few recorded delivery
forms to hand, so you don't have to fill it out in the post office.

A lot of things "get lost in the post" when I'm sure that most of them
get delivered fine, it's just ineptitude at the recipients end that
causes it to get "lost" there. I get the feeling that an item of post
delivered by recorded delivery often elicits a more professional
response.

Ahh, but it wasn't me posting it, it was Harrow-on-the-Hill station!!
They don't actually have an address on the form and it says to return
it to any station. The second form wasn't lost, as the helpful person
at the station faxed it through and phoned me to confirm that it had
been received at the other end