I've got a rattle.

[10G]

On the arm of the belt tensioner theres a cast hex. I think its 17mm, put a socket on this, a sliding T on the socket (if you have) then a long bar over the T handle for extra leverage. Pull on the handle, I think pull clock wise, to compress the small shocker thingo on the tensioner, it will only move maybe 10mm, but its enough to make the belt slacken off.
Just remember to take a pic of how the belt is before you remove it.

Thanks Mark I apprecaite the help.

Think I'll get a new belt and keep the old one as a spare. My old Navara did one of these belts once just driving along. Took out the bottom radiator hose & something else as well from memory. You don't go far once they brake.