OP
Octopus
Ok.now point us at anyone who operates such a scheme! Elecsa and the niceic have stated they won't run such schemesMsparks, if you want to certify someone else's Part P notifiable work then you have to become a "registered third-party certifier" by being accredited as a competent person by a "third-party certification scheme". Note that this is separate from being a "registered competent person" with a self-certification scheme although both schemes are run by the same companies.
This has only been the case since last month.
See https://www.gov.uk/third-party-certification-schemes-for-domestic-electrical-work