how can I access on-line a record of my recent journeys

It doesn't tell you how for the same reason it doesn't tell
you how to buy fish & chips with Oyster. Because I don't
think you can :-)

I don't know if you can check your usage online, but you
can ask for a printout from any London Underground ticket
office which will tell you:
* lots of technical information about your Oyster
* the last three season tickets that have been loaded
* the current balance on the card
* details of the last 6 journeys you made using the card

It's a long printout like a supermarket till receipt -- just go
and ask for an Oyster printout and hand over your card.

what if I touch in at a Zone 1 station when my Oystercard
has only a couple of pounds of credit left, but travel to a
zone where the fare would have been more than that -
can I top up at the destination or not).

The system will debit the correct amount from your card
(giving you a slightly negative balance), and then allow
you out of the automatic gates. After that, you won't be
able to get into the system through the automatic gates
again until you've added credit to your card in the normal
way (either at a ticket machine or online).


Matt