You should either use an installer who is registered with the competent person scheme or make an application to your local authority's building control department or approved inspectors.
Dylech ddefnyddio peiriannydd sydd wedi cofrestru â chynllun personau cymwys, neu dylech wneud cais i Adran Rheoli Adeiladu eich awdurdod lleol neu arolygwyr cymeradwy.