In the UK, parking opposite double yellow lines is generally prohibited, regardless of whether your wheels are within the lines, if any part of your vehicle (including the boot) overhangs the restriction. The rules under the Road Traffic Act 1988 state that no vehicle should park where yellow lines are present.
However, in some cases, you could appeal if there were unclear signage or markings, but generally, overhanging is seen as a contravention. If you're unsure, you could also seek legal advice or check with your local council, as they can provide specifics based on the exact location.
For more information, you can refer to official government guidelines or consult with legal advice.