The original cooker knobs on my Norman 20 have gone brittle and have started to disintegrate.I would be interested to hear from any members that may know where I can obtain replacements.
If due to age parts are not available ease a knob off and try a local scrap yards for old cookers. The spindles are usually a D shape in only a few sizes with metal clips on so you should find something to fit, or look on ebay you can buy universal knob sets with adaptors for different spindle sizes.