Although we are after a set of drawers in the longer term I can't presently justify the expense so decided yesterday to come up with a cheap short term fix. The photos below is what I came up with.
As you can see I raised the level of the shelf by adding layers of wood on the sides in order for me to fit the green plastic ammo boxes I have. I also designed the shelf to allow me to carry 5 jerry cans of either fuel or water in the back (which are easily accessible when the back seats are down). When i am not carrying jerry cans I place a board over the hole to give me a relatively flat surface. The hole underneath can be used to store things that aren't needed in a hurry.
Without the jerry cans I can easily store four of the big boxes and with jerry cans, two big boxes with lots of space for other things.
Cost: wood $60, metal brackets $20 and about $10 on screws +odds and sods.
When finished decided to carpet it which cost about $120 including glue.
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