Many Thanks Paul that is what I was thinking of doing, or something simular. For the time being I have fitted D rings to where the 5mm heater securing screws are on the bulkhead and shelf. I have changed the 5mm screws for 5 mm stainless bolts. I have then used bungee cords and some foam to fix the jack,handle and wheel brace in front of the heater. when I am back from touring with the car this summer I will fabricate the alli box simular to yours. ( I hadn't thought of over hanging it closer to the distributor, good idea).
Many thanks again for your response and photos. Cheers Les