Found a Land Rover specialist who can remove the bolts for us. It was looking like a load of hassle. Land Rover fora all said its a PITA and either needs welding a nut on or angle grinding a slot but there is carpet which may go up in flames. Best to get a professional to do the work.
Those security bolts are a right fuck. Cutting slots is hard work and you'll go through a fair few discs using a dremmel... My guess is they'll go the welded bolt option. Anyway hope you get it sorted.
Cunts.