Thank you all for your input, lots to consider here.
Almost finished motorising the collimating lens, I wrapped a 3 mm wide strip of Velcro round the edge of the lens which grips the belt and works best at fastest rotation speed setting on the handset.
I will test the system and make any changes as necessary as per your suggestions.
Once complete, this should be a more user friendly set up and relatively cheap to convert.
Regards,
Jack
Essex UK