Long Ranger tank and ARB Towing Hitch
I've been looking around at long range fuel tanks and ran across this problem also.
The advice I've received is that the LR tow hitch will have to be replaced with an ARB tow pack. The rear step will also have to go in the process because it doesn't fit once tha ARB hitch is installed.
Why, because the ARB Tow Pack has been designed to fit with the Long Ranger tank but ARB weren't concerned about the step.
From what I read above, this is exactly in line with BlueWagon's experience.
I'm confident that this advice is correct.
On the other hand if there's been a miscalculation by LR in drilling holes in the chasis ...... good luck !