is there room in the head to grind a slot in it for a flat head screwdriver?
Or can you JB weld a piece in there so you can then remove it?
Or maybe you can have something welded on it to be able to remove the bolt.
'92 300CE - Sold
2004 C240 - C7 Wheels
2015 ML350 - P1, Pano, Ash poplar wood, Sport Dinamica interior, Running Boards Keyless go.