I know your comments are addressed to Nick, Vivienne but he may not see this thread for a day or two.
So, I mention that the driver would be in the lower vestibule and by noting the position of the trolley pole the vestibule would be the one in the right hand side of the 'photo. As you may well know most tramway systems did not have turning circles, such as that at Rednal, therefore the trolley pole would be reversed and the driver take up position at the other end of the car. Judging by the gentlemen's headgear I believe that is the driver sat upstairs partially appearing not to be included in the 'photo. For anyone with access to the National Tramway Museum at Crich, Derbyshire, I would say go there when you can and get some tram rides. I went some years ago: it was good then but has been even further improved.