Do you have Part 16 on diagram - The plastic cover?

Yes, it looks like there are 3 options depending on the colour. Please see below links: 968/99901W - White Belt Guard https://www.lsengineers.co.uk/catalog/product/view/id/191560 968/99901Y - Yellow Belt Guard https://www.lsengineers.co.uk/catalog/product/view/id/191558 968/99901S - orange Belt Guard https://www.lsengineers.co.uk/catalog/product/view/id/103631