Dave Arquati wrote:

£1.10 Fulham Bdy
£1.80 S Harrow - Fulham Bdy

I was more annoyed that the helpline said they couldn't do anything,
than that the unresolved journey got onto the card. I'm usually very
forgiving but it strikes me as odd that it's OK for LUL not to refund
an
overcharge when the card is unregistered, although perhaps there's a
good reason for it.

Surely it doesn't matter whether or not the card is registered? Your
mate purchased £X of prepay to use to make journeys with an Oyster
Card. He is now unable to make £X of journies due to staff
incompetence so havent TFL breached the contract? He could spend
£100+ taking them to a small claims court