Unless you have permission,  you may only feature members of the Royal Family in pretty limited circumstances, whether in TV advertising (which is covered by the BCAP Code) or adverting and marketing in any other media (which will usually be covered by the CAP Code).

When there's a royal event or occasion such as a royal anniversary, birthday or new baby on the scene, it may be possible to make various references, provided you do so without creating the impression of patronage or endorsement by the Royal Family.

However, you must not feature the Royal Arms or emblems in advertising/marketing materials.