Tom Barry wrote:

(there are presumably routes wholly within London you can still *buy*
booze on the train, surely?), but I've no idea what powers he actually
has to do this (he does have them, presumably?)

Are there actually any *wholely* within London for which this applies?
I can think of examples of trains that go between two places within
London that serve booze on the train (Liverpool St to Norwich between
L.St. and Stratford, for example, but I can't bring to mind any
*wholely* within London ones that serve booze on the train.

Robin