[Dave Moll]

As the paster diagram is the bell, I have used Bn numbers therein, reserving Tn for the telephone, so yes, B1 is the earthy end.

Although swapping A and B on the way into the bell resulted in the bell not working, as the ringing current was between black and red, this does give me an idea - I will try swapping red and white between the bell and the telephone. This would have the effect of placing the A leg on the cradle-switch side and the B leg on the LD side as you have suggested.