I am not a legal expert, but I can provide some general information. In the UK, altering or modifying a vehicle's badges or emblems could potentially be considered an offense if it involves misrepresentation or falsification of the vehicle's make or model. The precise legality of changing badges can depend on the specific circumstances and the intention behind the modification.
If removing a superlight badge and replacing it with a Harley-Davidson badge leads to a misrepresentation of the vehicle's make or model, it may potentially be seen as a violation of the law. Misrepresenting a vehicle's identity can have legal implications, including potential issues with insurance, registration, and compliance with regulations.
To ensure compliance with the law, it is advisable to consult local traffic laws, regulations, and the guidelines provided by the Driver and Vehicle Licensing Agency (DVLA) or relevant authorities in your area. Additionally, seeking advice from a legal professional or contacting the DVLA directly can provide you with accurate information regarding specific modifications and their legality.