All it takes is a VOSA inspector at the side of the road pulling in random vehicles (of course they wouldn't target any specific vehicle groups when doing this...

) and you can watch all of your hard work and hard earned get put in a crusher.
They don't charge you to watch!!!
Of course there are all sorts of arguments that you've told the insurer about it, but at the end of the day, the V5 will still say it's a Range rover......and it's not, therefore all of your tax, MoT and Insurance become invalid. I value my driving licence......... but feel free to take your choice.