What

Update the Colour page on the website in response to the refreshed colour palette.

Why

So users know what has changed and which colours they should use

Who needs to work on this

@calvin-lau-sig7 @CharlotteDowns @owenatgov (to detangle current PR)

Who needs to review this

TBC

Done when

• Detangle current colour PR to have a separate PR for this work
• Decide which colours belong at component level, and which component specific
• Draft updated guidance for the Colour page
• Create and review PR, ready to merge