Hi Leon,
I would like to echo Merv's comments......your a lucky chap!
If you get an accessory fuel filter consider a 30 micron filter fitted BEFORE the factory filter.....something like this
http://www.ebay.com.au/itm/Diesel-fuel-filter-water-separator-universal-pre-filter-Common-Rail-Diesel-Kit-/401318441627?hash=item5d7071729b:g:EsgAAOSwT-FZBtx6 they are relatively easy to fit & plumb up. Fitting one of these will extend the service life of the factory filter (which are expensive) change the accessory filter say every 2nd oil change for about $30....cheap insurance.
If your still at Gosford, jump on the M1 and give the truck 'a flogging' (so to speak) to give it a good clean out!
Re silicon sprays, don't believe they will cause any problems (hardening)....but using silicon/silastic type adhesives/sealants during component assembly can cause problems with O2 sensors....the fumes given off during the curing process cause the problems!
Re fuel.....95% of all fuel is now imported (Singapore) regardless of 'brand' it all comes from the one depot and depending on brand additives they are added/blended whilst the delivery truck is being filled.....fuel from the depot you can bet your right testicle will be clean.....contaminants are picked up from servo underground tanks regardless of brand.
Always look for fuel at outlets that would have a high stock/fuel turnover!....you would have to be very unlucky to pick a load of bad fuel.
Adding extra 'additives' to your fuel.....make up your own mind.....myself,..... diesel fuel in Oz is Ultra Low Sulphur content, making it a very dry fuel. To every tank full (250L) of fuel I use, put in 1/2 liter of two stroke oil or auto trans oil (cheapest available) just to increase the fuel lubricity......works for me.
Travel safe,
CU down the road.