Non Corridor Multiple Workings

[TEW]

I haven't seen the gangways physically connected lately. Or I could just have not looked hard enough.

Connecting the gangway is not optional, it happens when the two units are coupled. There are then just the end doors on each unit which need to be opened, but that can be done in a few seconds.

 

[mmh]

Is the question here actually "on a service with a guard must the driver and guard between them be able to access all parts of the train without leaving it"?

There are loads of examples of that not being the case. In the south until relatively recently it happened on single units. Triple 171s have been mentioned as a current example, I'm reasonably confident I've seen quadruple 171s. On a two unit train the guard might or might not be in the rear one.