VW say the average time from factory to dealer is 4 weeks. That can be broken down into time waiting for a ship, journey time to the UK, offloading and distribution to dealers. Surprisingly, the bit in the middle is best defined.
At the moment, a vehicle transporter ship leaves Setubal for Sheerness once a week (currently around Friday/Sat). The journey takes about 3 days then 12-18 hours in port for offloading, but if you live further north your car may be offloaded at Grimsby (another day's journey), or at Tyne (another day again). Once offloaded, it will take a few days up to maybe 2 weeks before delivery to the dealer.
So to achieve 4 weeks from factory to dealer requires cars being loaded on a ship roughly within 2 weeks of leaving the factory.
I got the text message telling me my car had 'left the factory' on Sunday 31st March and as far as I can determine from the dealer and VW Customer Service, it is still waiting for a ship. So that's already over 2 weeks, in which time 2 ships have left Setubal for the UK.
After experiencing nearly 9 months wait for a confirmed build week, I don't have much faith in VW claims and promises. If you raise your expectations you will most likely be disappointed and then angry.