I have this,not being used since i put everything in a lwb transit 350 last September.
It is an Ifor Williams BV84G ,it came with the alloy side boxes,i fitted a roof rack.There was a boiler in it for hot wfp hence the chimney but i took it out as it was in the way.
Payload is about 900kg.Pics show how it is today,housing a giant haddon rocking horse etc .There are some heavy duty hangers that attach internally and happily take about 40m of thick hose in a figure of eight and i had the washer at the rear doors.So the box is 8x4 internally plus the cone bit which makes a great place to take a pee!
My number is 07949002001 if you want to speak about it.