I think the "headed" threads seem like they would accept some sort of torx "socket" from the outside of the vehicle
But attached is a photo of behind the right-rear wheel arch liner, from where the bolts can be unscrewed with a standard hex socket.
As the bolts were a little corroded in here on mine, I replaced them with some stainless bolts and nylon washers..
Easy enough to replace.
Cheers,
Karl.