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The trike doesn’t need to have the two wheels at the back, Yamaha do a TriCity 300 which can be driven on a car licence. Just make sure if you do go down that rabbit hole that the spacing between the wheels is wide enough to qualify as trike and the length is short enough to be congestion charge exempt. AFAIR the French trikes are too long and the big TDF three wheel camera bikes are too narrow to be a trike.
I admit, the idea of a motorised tricycle isn't really my dream.