In message , at 09:38:24 on Wed, 2 Mar
2011, Roland Perry remarked:
And I have to contact TfL in order to transfer the Oyster Credit to a
new card (or to otherwise rescue the credit if Barclaycard cancel the
card because I've been naughty, or indeed withdraw the Oyster-ness for
no reason whatsoever).

And I see that Tfl have a (very long) webpage about this:

http://www.tfl.gov.uk/tickets/15541.aspx

Here's what they say about "PAYG only" OnePulse cards:

1. Simply continue travelling until your credit is used up. Your
original Barclaycard OnePulse card will still work as an Oyster
card after the credit card expiry date. Be careful to keep your
original card separate from the new one when you travel to avoid
the wrong card being charged.
or
2. Transfer the balance to your new Barclaycard OnePulse card online.
or
3. Request a refund at a Tube station. If you can't reach a station
easily, you can send your Barclaycard OnePulse card in to us at:
Oyster helpline, 1st Floor, Albany House, 55 Broadway, London
SW1H 0BD.

#2 works fine apart from two minor issues.

When it asks for a memorable date it needs dd/mm/yyyy and *not* dd/mm/yy
that it asks for. I'm especially sensitive about this bit of tomfoolery,
because it caused me to lock out a different one of my CC's last week.

And when you get to the end, having requested a transfer to the new
card, it drops the bombshell that you have to collect it within 7 days
from a specified station!!! Yes, that old banana skin again. And guess
what, I'm not travelling until about a week after that.
--
Roland Perry