thanks for the fast respone, I am at work but took my lunch half hour to take a look. If you mean the front cog being loose on the mounting flange it doesn't seem to be, when you move it the whole assembly moves a little on the bearing.
I have 2 issues.
1. the whole motor unit is loose in the BB. in top gear, wheels on the ground, if you jab the throttle to make the motor run the motor unit can be observed moving in the BB. Not just rotationally but up and down too. This is a bit worrying as it was a super tight fit when it went in scraping the black paint off and requiring winding/ screwing to make the motor saw its way into the BB. Clearly there is some deformation now or at least it needs tightening or shimming to fix.
2. The bearing noise is still present but not all the time, there is a roughness to the whole motor and by grabbing different parts with my hand whilst pulsing the motor on/off I believe the issue to lie within the front part of the motor (the round barrel bit with moulded cooling fins on it that says 8FUN). The part that the front chainring attaches to which I would class as the 'final drive' part seems to be quiet now having removed the scraping debris using my earlier air/pb blaster efforts.
I am not entirely familiar with the internals of this motor but I suspect maybe nylon cog or a bearing in this area or a broken bit in there.
I will of course try the front chainring first though as you suggested. I thought I could get it off with the motor still in the frame by rotating the wheel and putting a screwdriver through from the other side of the bike. The reason I am reluctant to pull the motor is that the wiring is all run incredibly well in a stealth fashion! Needs must though.
I think the product is superb and would buy another one tomorrow.