VATREG46150 | Registration of persons who make taxable supplies in the Isle of Man: action to transfer a registration from the IoM to the UK register

From HM Revenue & Customs · VAT Registration

If it is agreed that a trader should be transferred from the IoM register to the UK, upon receipt of the relevant papers, you should action the transfer as follows:

Process a proforma VAT 1 in the normal manner, transcribing the current registration details and including the UK address. Note the front of the VAT 1 that this is a ‘pro forma IoM registration’. The stagger code can be obtained from the details provided by the IoM service. The effective date of registration will be the same as the date of transfer.
Do not issue the VAT 9. Inform the trader in writing:
of their new registration number
that their registration has been transferred to your office
that a new certificate of registration will be issued in due course.
Issue the VAT 4 to the trader with a covering letter advising that the registration has been continuous from the date they were first registered in the IOM. Provide a precise date.
If applicable, pass the folder to DMU to liaise with the IoM Service about recovery of any tax outstanding from the period prior to the transfer.