You may need an Economic Operators Registration and Identification number (EORI number) if you move goods:
- between Great Britain (England, Scotland and Wales) or the Isle of Man and any other country (including the EU)
- between Great Britain and Northern Ireland
- between Great Britain and the Channel Islands
- between Northern Ireland and countries outside the EU
https://www.gov.uk/eori
You can choose to register for the VAT IOSS scheme to report and pay VAT, if you sell goods imported in consignments with a value of £135 or less (known as low value goods) from countries outside the EU and Northern Ireland, to consumers in the EU, Northern Ireland, or both.
https://www.gov.uk/government/collections/vat-import-one-stop-shop-scheme