Nice shot, Mike. Car 342 was first to have an enclosed balcony, far more 'enclosed' than was later standardised on. The enclosing of 2 axle double deck trams on narrow (3' 6") gauge lines was frowned upon by the 'powers that be' in Westminster, but 342 remained enclosed for the rest of its days.
Here it is at Bearwood Road terminus of route 29, probably at the last day or two of operation of the Dudley Road routes in September 1939. Photo by the late Ray Coxon - that's his Centric bike propped against the kerb in the foreground. He was still riding that bike in the 60s and 70s when I knew him - including to and from Weston super Mare to visit relatives down there! A piece of Birmingham transport history in itself!