I've picked up another frame for my Sport as the original is too badly bent on the front downtubes and top tube, The frame I've picked up is perfect.
There are a couple of minor differences,
A strip across the frame is present on the red frame, aswell as the lug/tab coming downwards. Also the battery carrier is different, the red frame has a straight strip across, the black frame has this strip at a inclined angle, aswell as the tray being part of it.

The ignition bracket on the red frame is welded to the frame, where as the black frame I had a separate bracket in my box of bits.

Both frames should be Sports's, the black one is the original off my bike, both have a A/3 frame suffix, the red frame is a couple of thousand later on the serial number though. Are the various brackets year related?