In message , Dave Arquati
writes
You can't put on less than £5 at a ticket machine (or that might just
be for debit cards, because I never top up with cash). I'm afriad I
don't know about the ticket office, because at Gloucester Road there's
always a huge queue of tourists so I avoid the office when I can.

You can top up with a small amount of cash on a Multifare machine
providing it is accepting coins.
--
Kat Me, Ambivalent? Well, yes and no.