I cleaned the rexine material covering the cabinet using plenty of foam cleanser and a toothbrush to gently remove the dirt - any tears were fixed down with superglue.
The grey plastic front was removed and cleaned by submerging it in warm water which had a little washing up liquid added.
The dial glass is made from perspex in this set - it too was removed and the outside carefully treated with a soft cloth and Brasso which polished out many of the fine surface scratches and gave it a nice shine.
The legend side of the dial was left untouched and carefully protected whilst carrying out the cleaning and polishing operation.
I also managed to find a suitable brass bright of the correct size in my spares box which was cleaned and attached to the tuning knob.