Thanks Sparkychick as well...
I beat the back panel out and stuck some 3M sticky back mastic strips we use in work for making safe exposed cutouts etc over the inside of the back panel around the burn marks to extra insulate it...
Put it back in last night.. no tripping, ran on every setting for half hour all seems fine, except one oddity??
When set to LIGHT only, which in manual says
"For a light with NO cooking function"
The grill element comes on & off if I turn the temp dial...!!
Any ideas??