Looked into spacing the tow-bar further away from the rear valance, and removed the bumper from the bar......fixed with M6 nuts and bolts! Should be 5/16 UNF, which is whats going back in. In the end the irons bolted to the body are too short to enable moving the whole assembly. Bugger. In reassembling it all I find something odd (apart from the overriders being handed) - the RHS boot edge as it opens is barely clear of the overrider top edge, despite it being barely clear of the reflector, while the LHS boot lid is well clear of its overrider. Will get under there again and measure some things to see where the discrepancy starts from.