I assume it is too much to expect this to mean that one fare would allow
unlimited travel for an hour (the way many continental systems work) but
we
will see yet more complexity added to an already over complex system?

(some systems, I think Berlin, now explicitly disallow a return journey
for
the one fare, even if within the hour)

It seems to me that once you start having tickets with certain time limits
on them (e.g. single tickets on Tramlink being valid for 90 minutes from
issue) this has to be the way you go.

What is the situation with tickets issued from kerb side ticket machines in
the central London pay before boarding area and at stops served by bendibus
routes? Presumably they must have a time limit on them. Are they also only
valid from the stop they were issued from? What is the mechanism to stop
them being presented more than once or isn't there one?

G.