Registration in respect of distance selling from other Member States: requests for retrospective registration
Schedule 2, paragraphs 3(2) and 4(1) only allows traders to negotiate an earlier date of registration at the time of application. However, they may not go back more than 3 years from a current date.
If a trader who is already registered asks to have his EDR backdated retrospectively, you should refuse.
If a trader has been registered previously but is not currently registered, you can backdate his new registration as far as the date of the effective date of cancellation if he had an entitlement to be registered for the whole period.
Further guidance can be found in VATREG25000.