This part of GOV.UK is being rebuilt – find out what beta means

HMRC internal manual

VAT Groups

Eligibility for VAT group treatment: control conditions: overseas control

The fact that the controlling body may not be established in the UK or have a fixed establishment in the UK does not exclude its UK based subsidiaries from becoming members of a UK VAT group. However, under these circumstances, the controlling body itself would not be eligible to join the group.