Diesel Heater Install.
Here's some pics of my diesel heater install into my van. Hope it helps other Discovery/Journey owners. Was quite simple and I think the positioning within the 17.55-5 works okay. My only concern was adding the extra weight to the front corner where the battery and gas bottles are already.
Parts I used.
The heater unit. Worked out to be $562 AU, after conversion. It came with piping and the digital controller (which I did not ask for)
I purchased
this diesel tank from Supercheap Auto. Drilled a hole on top and fitted pipestand supplied with heater. Fits nicely in the front boot and I gave some extra length on the fuel line to remove for filling.
Heater unit placed under the front lounge behind battery. Hole sawed two holes for the exhaust, external air intake and fuel line.

Position of the heating vent allows to direct heat up middle of van or with the directional vent towards people on the lounge.
Digital controller mounted against cupboard beside lounge. I found that the ambient temperature of this controller is not accurate. Doesn't matter as I run it in manual mode with the heater constant at a % power seating. If you have it on auto it cuts in and out which drains your battery quicker.

If you have a Drifter Control Panel connect the negative (black) wire as shown (one I'm holding), so you can see the power the unit is drawing. It draws about 8amps on startup for about 2mins. Once going on full power it draws around 1.3amps, giving about 70hrs running time. When on 50% it was about 0.5amps giving around 150hrs. In comparison it is using the same amount of power as the two LED ceiling mounted lights in your van. So I think that is pretty good. Also note when you reduce the power of the unit it is still blowing the same temperature air, only the fan slows down.
This unit has a wire marked 'night light' which I disconnected, as it illuminated the controller constantly and was too bright when sleeping.
In order for the unit to draw air internally, rather then putting an extra vent in, I just drilled some holes in the top of the fire extinguisher recess. Seems to work fine.
For the muffler, I used 2 of
these, pinched some insulation from the ceiling, and pipe from a disused trampoline safety net. You can buy one for $40 on ebay, but I was bored.
In mounting the fuel pump I used a piece of discarded sullage pipe. This stops the 'tick' being heard inside the van.
So underneath it looks like this. Power to the fuel pump comes by drilling a small hole from under the lounge into the front boot and feeding it under the van via the water drain holes. The fuel line feeds through that same hole as well.

The external air intake I fed into a piece of PVC pipe with some insulation in the end to silence the noise. Noise wise externally I would say slightly louder as a A/C unit.
Lastly I sealed where I had drilled through the floor with some high temperature silicone to prevent any issues with dampness. The wiring for these units are 'plug and play' so you don't need a to have soldering skills. I did cut some of the wiring and resoldered to minimise lengths though.
I have used it in -2 degree temperature with no issues. It was particularly useful when pulling over for lunch whilst on the road, brought the van temp from 5deg up to 15deg in about 10mins. Best of all my wife was sceptical of me putting it in, but now she loves it.