Hardly a new idea. BMW did it in 2005:Now I know it is a wind up, EV MoHo.
I want to do more than 100miles a day, hopefully JCB's converted to hydrogen engines will be the way.

BMW Hydrogen 7 - Wikipedia
Hydrogen combustion engines are a lot less efficient than a fuel cell. And the high combustion temperatures mean you need all sorts of emissions controls to reduce the nitrogen oxides. If you're going to convert your fuel to hydrogen, you may as well use a fuel cell and electric motor.