So,
Swapped the bezel off a clear aluminum E07, did not disturb the optic at all.
Stopped working!
All I was getting was the two lights on the switch (out of 4). No response, no flash.
Swapped the parts, another head worked on this body, this head did not work on another body,
Spring has a glob of solder in it, and might have been too compressed. Pulled it up a little with a needlenose.
No joy.
Cleaned the tube and contacts on the head with a Q tip dipped in alcohol.
Some black stuff came off onto the cotton.
JOY
Seems to be working again.
Oh the joys of flashlights!