The platter components laid out. I tapped the Acrylic to accept M4 machine screws which will secure the magnet.
The Brass adaptor to the right was made for me by a local model maker, http://www.ne3d.co.uk/ it slides over the existing brass bush and is secured by grub screws. This is machined very accurately, centres the magnet and provides a platform for the position detection hub at the correct height.