Paul - not really
Historically the three wheeler came to prominence as a result of cheaper road tax than a four wheeler in the UK. Marketing stressed the attracting to the 'sporting man' who either wanted something a bit more, or who now had a family. Whilst they are the least well surviving model, the various versions of family Morgans were produced in large numbers.
There have been oddities in the legislative approach since the dawn of motoring.
But that's history, no real idea as to the present.
I did post this elsewhere and an MP in the Department of transport is going to seek clarificaction
