The thick donut part is whats left of the internal casing, I cut it back to just above the groove that holds the circuit board and wrapped a bit of narrow sticky tape around to hold the two halves together. I did try it without removing the lens holder but found it was giving slight vignetting.
It seems the internals on the different models do vary, Lee's one has wiring thats a mirror of mine. I have 3 resolution settings in the software supplied with mine, face tracking and a zoom facility. I bid on one of the early models, but I think the one supplied was the later one (gotta be lucky sometimes
)
Cheers
Bill