If the design in question was registered before 9 December 2001 you may apply to cancel it. The grounds for cancellations can be found in Section 11 of the Copyright Designs and Patents Act 1988.
At any time after a design has been registered, you can apply to the registrar for the cancellation of the registration of the design on the ground that the design was not, at the date of the registration, new, or on any other ground on which the registrar could have refused to register the design.
Also, you can apply for cancellation of the registration on the ground that (a) the design was at the time it was registered a corresponding design in relation to an artistic work in which copyright subsisted, and (b) the right in the registered design has expired in accordance with section 8(4) of the Copyright Designs and Patents Act.
If the design was registered on or after 9 December 2001 you may apply to invalidate it.
A design may be invalidated because it was not new or lacked individual character when compared with an earlier design at the time it was applied form or other reasons under the amended law.
The grounds for invalidation can be found in Section 11ZA of the Registered Designs Act 1949 as amended.