Dirty/muddy fuel

[dom14]

I live central qld but last time the car was off road was about 2 months ago and that was just a 100km dirt road no water crossings. my neighbour gets diesel at same servo as me and he hasn't said anything about his filter. Starting to think maybe I should drop my tanks and have a look?

I would encourage to do that. From what I've heard diesel tanks can build up gunk inside lot quicker than other fuel.
The water is the source of the bio contamination according what I've read. Removing the tank and clean it properly with suitable
solvent and then fit it back with a good cleaner additive to remove a residue/clogged up bio or otherwise gunk in the plumbing.

Don't compare your issues with another guy that gets his diesel from the same servo. He may or may not be developing the problem.
Servo underground tanks are notorious for water contamination(I used to water and contaminant testing on underground tanks).
Diesel mixes with water better than other fuel I think, hence the reason for bio contamination risk being higher with diesel.