Smart charge relay

Yes you are right but I do not think you are seeing the whole picture.

Run a new 6mm2 from the battery with a 30A fuse at the battery end.

I run this into a further fuse block, 20A 20A 10A

Then just pick you split charger and controller and wire accordingly to the plugs at the towbar. This will work and dependant on the age of your vehicle you should have few problems.

But

I think what the fitters are using is a dedicated loom that will pick up a pre-installed feed in the rear of the car but you generally can only use this with a dedicated loom as it includes control cables to enable associated system as well. A dedicated loom is easier to fit and ensures that any onboard warnings are enabled.

but the wiring diagrams of the relays say to take a wire of the battery as with the light relay can get problems as i did with a car as the new light relays have to have a live to them as well and you cant use the same live in the boot for both i had a fitter out 4 times with a big problem and still did not sort it out cus he was to lazy to run a 30 amp wire from the cars battery to the boot 

Freelander 1 or Freelander 2?

Freelander 2 is very difficult to get a cable through the double bulkhead, no wonder the fitters don't want to do it. There is a dedicated fuse in the boot junction box for the purpose of the fridge and charging that a dedicated loom would use, but can be adapted for whatever use.

Iv got a freelander 1 and going run the wire under the car to the back as iv looked under it and can cable tie it to under the car and saves getting the cable inside the car as I'll not be going off road I'll never ground the car to damage the cable 

Why not just use the fuse that Metheven referred to? 😞

Don't think a freelander 1 has the live in the boot same as freelander 2 I'm trying to find out if it dose