Latest Update
The Cruising Association’s latest position is that “for VAT purposes, the relevant day moves to the end of the transition period as the UK will remain in the customs union during this time”.
Hence Brexit Day, for VAT purposes, now extends to the end of the period for trade negotiations which Boris promises to be completed by the end of this year.
More details at https://www.theca.org.uk/news/brexit_preparations_brittany