Ideas bouncing round my head about building an L7e Heavy Quadricycle (Goods).
Goods has a weight limit of 550kg, not including fuel (for EVs, not including traction batteries).
Power is limited to 15kW.
550kg + 158kg battery (~20kWh, using Leaf's density, wiht a 90% usable capacity threshold) +80kg driver + 20kg other stuff = 808kg.
With a reasonable RR of 0.02, and Cd 0.4, area 1.2m^2, 60mph should take 10.3kW, 70mph should take 14.5kW. Range at 62mph would be 112 miles (not allowing for acceleration).
Regs don't seem to specify what the requirements are for "Goods vehicle", but this might change the insurance categorisation. As an EV, VED should still be £0. To make an aerodynamic "goods" vehicle, I'm thinking pickup with a cover, so not brick shaped.
Mini Mokes were about 550kg, and a dry A-series engine and box is about 105kg. Caterham 7 chassis are under 50kg.