Bump and edit:

Clutch cover used and would also say standard.

Pull out on the lever with the fan picture on it. One click is slow speed, two clicks is high..
You can either have it come from the vents under the windscreen (defrost), your feet or the cabin.

Generally the best (and right viscosity) you can afford is a good rule.

I figure it as what is your motor worth and how much are you prepared to pay to keep it in good condition?

16.5kg apparently..

Is the relay clicking when you turn the key? All you need for the relay to work is 85 and 86 connected to switched +12V (ignition) and earth. Then when the +12v is supplied the relay should have an audible click? This means the switch in the relay is working and that would then connect +12V (battery) to the pump.

Thanks. Yeah, value is in the eye of the beholder (or person who desperately wants it) really isn't it..
It's weighing up the convenience of knowing where this one is vs trying to find one at a later time when you want one..

What is a 4.8 worth? Are they hard to find? Have possibly found one but unsure on their value?
Realise they are more a competition ratio but if the price is right it's always good to have in the shed.

Can anyone tell me the weight of just the H165 diff head (not the complete axle assy). The wiki has the complete axle assy weight but not just the head.

You can try a radiator flushing additive but I'm not sure on their effectiveness.
Otherwise a garden hose and flush water through the cooling system (from both top and bottom hoses) until it runs clear, then refill with proper coolant. Don't forget to turn the heater to hot so it gets flushed as well (I usually disconnect the heater and flush it separately to ensure it is done properly as well).

Other than that you will need to remove the radiator and get it flushed/rodded out professionally.

EDIT: IMPORTANT: Don't forget to bleed the cooling system afterwards. Fill it with coolant and run the engine (with no radiator cap and heater on hot) until the thermostat opens (you will see (hot)coolant flowing rapidly across the top of the radiator), then top it up and shut the engine off, leaving it to cool comepletely. Once cold, top up the coolant and put the radiator cap on.

Not worth it, much better off just getting a pair of halogen replacement units. Better beam and able to just replace bulbs from there on in.
Mind you, a 2nd hand sealed unit from the wreckers (if you can find one) is prob only $10 or so.