Many thanks for that informative and helpful comment Sir. I reckon its a 2022 or2023 e-mythique and assumed it would be CANbus (the new display is a c245 instead of the original c244) . At any rate neither display seems to work and the bike survived a couple of real downhill workouts including a couple of shallow burn crossings. But it got me home in better shape than I (two front teeth) or so I thought for it hasnt started since. No rain, no submersions and it's reading 40v at the WD60? connection to the motor. My experience with bafang bbs02 motors suggest they eat controllers, but I know nothing of these lovely wee M510 units. Im trying to source better parts, motor and wiring diagrams as those I downloaded initially were fairly basic, as indeed am I in this respect.
It's a shame because I enjoyed the bafang motor way more than the older Bosch and Shimano and even Sportsdrive motors Ive tried. The M510 is alot more powerful and has a lovely over-run that keeps you moving for a meter or two after peddling which is so handy for steep, punctuated climbs. Both their line of motors and batteries seem very reasonably priced compared to a replacement Bosch part, as you would expect, but Bosch seem so much more reliable in my fairly limited experience, and that is what we need.
Apart of course from further advice or suggestion on remedial action to get it fixed.