You implied it!

"I've got a Transit Connect"
"It's my van that I paid for"

The person who pays for the vehicle is the owner - the V5 actually says that the registered keeper is not the owner.

If you need to claim, where is his "Beneficial Interest" in a van that he neither owns nor uses?
And that's before the insurers start talking about risk-profile for a young inexperienced driver versus a more mature and experienced one.

Your van, your call, but I don't approve of some people circumventing the rules when that then has an impact on the premiums I have to pay (something like £30 each) for uninsured drivers, and that is what you could end up being in the event of a claim.