If you believe Clarkson's column in The Sunday Times, the crew really does have a problem coming up with a name, and the few ideas they have are already registered trademarks. If worse comes to worse, they could lean into the joke and be (deep breath):
But that might be too long for Prime's interface to display. It's also quite possible this is a well-planned publicity stunt. The trickle of funny videos and tweets do a fantastic job of keeping the guys' names in the news until the show actually starts streaming later in the year.