Following the query I raised here about Metronet a couple of days ago, I've
just got a response from them that indicates they don't object as long as
certain security precautions are observed which would be the same in any
wireless config I guess.
The relevant paragraph from their reply is this:
Basically, you are more then welcome to do something like this, but you
need
to be aware that as our customer, it is you that is responsible for
making
sure that any traffic that is transfered over the connection is in
accordance
with our acceptable use policy:
http://www.metronet.co.uk/policies/aup