Good news! Looks like Tesla is preparing to bring Model 3 to Europe:
Tesla Registers 17 LHD Model 3 VINs — Comin' To Europe, Baby! | CleanTechnica
The VINs registered are Left-Hand-Drive and one digit indicates it is for EU. So obviously for Britain. I am actually surprised that the first EU VINs we are seeing are LHD. So it would seem they are bringing Model 3 to all of Europe at once? Most likely to make full use of selling the expensive Performance and AWD Models in as large numbers as possible as they are doing now for the US.
I am also surprised that there have been Model 3 in Australian show rooms already but not in Europe. Does that have to do with a (possible/likely) different charging connector?