SJCWHUK wrote:
You obtain a receipt from the large ticket machines (if you use this
for top-up) do not just expect a credit card voucher.

If you only travel to London on business then this should be enough
to satisfy your company and the Inland Revenue when they come to go
through expense claims.

If there is any question over what trips you have made which are
business/personal remember the ticket office can give you a printout
of the last eight journeys on your card.

Sounds good to me, thanks. I did a bit of digging since my original
post, and it seems I can top-up with small amounts at a machine and
get a receipt (it's only by phone or online that the minimum recharge
is a tenner), so in practice what I'll do is pay for one journey in
advance so that on my next trip I'll have "a round in the chamber"
when I arrive at Heathrow. I can then avoid the queues and top up
with another £3.80 during the day when the machines in central London
are quieter.

If the receipt proves I used a card ending X to pay £Y at a Tube
ticket machine, that'll satisfy the bean-counters at work, just as
it does for buying singles or LT Cards now.

Thanks to everyone who responded.
--
Paul Robertson )
Glasgow (remove zzz from above to reply)