Thanks for that Charlie.
I had the same problem in my old Range Rover. The previous owner had put higher wattage bulbs in and it had melted the insides of the switch. I fitted relays and immediately got brighter lights and no more melting plastic smell from the dash.
Today I didn't get much done. I had to take the cat in to the vet for his yearly grease and oil change. Earliest I could get in was 10, so that disrupted most of the morning.
I made a list last night of bits I would need and managed to get an assistant at the local Repco that actually knew his stuff.
I showed him the mounting system for the old headlights and he dug through his books and told me he could get new bulbs for them, but they would still be 40/50W. There was nothing listed that was brighter. The other issue with using different bulbs would be that the shape of the reflector means that I would have low and high beam, but they would both shine straight ahead, potentially blinding oncoming drivers. No chance of that with the bulbs in it now.
He made a few calls and found another alternative. I still use the inner and outer mounting rings, but the whole reflector is replaced with a modern version that takes regular H4 bulbs. I will have to make an adaptor for the cables, but that is easy enough. I got the semi-sealed reflectors for $60 a pair, which is almost half price.
While there, I got a new high/low beam dip switch, a non-load dependant indicator flasher unit, new park/indicator bulbs, heatshrink and some heavy duty bullet connectors and spade lugs. The new headlight reflectors won't be in until later next week, but that's ok. I don't have the time to do them tomorrow.
Once home, I started by disconnecting and removing all of the added in wiring. It was surprising just how much there was, and this is without counting the heavy extension lead cable running to the back indicators.

With that all out of the way, I started reconnecting the original wires. As the rear indicators are not connected to the original wiring, I left those unplugged for now. I rewired the high/low beam dip switch and now the headlights work, although they are pretty dim. I'm only getting 11v at the dip switch, so I have a few connectors to clean or replace. The front parkers worked also.
I have power to the flasher unit, but it is not making it back through the indicator switch. I pulled the horn button out and found everything is missing from under it. I think there is supposed to be a spring and a contact, with a red wire running down the steering column and going to the horn. A previous owner had rewired the horn to work off a button on the dash, but I found the original wires at the bottom of the radiator. They have been cut short, so I will have to get under there when it's dry and try to work out where they connect to so I can replace them.
With the horn button out, I was able to undo the nut holding the steering wheel, but can't find my steering wheel puller. I've seen it a dozen times recently, and even remember putting all the different threaded bolts back in the kit after knocking it over, but can't remember where that was. I need a big shed.
Once I get the wheel off, I can pull the indicator switch out and give it a clean. At the worst, Iveco still sell the whole assembly, so I can get a new one if this one is too far gone.
While trying to get the steering wheel off, I happened to look up at the circuit breaker panel and saw something odd with the wiring. I removed the cover and peeled back about 6" of tape and found that at some point, the wire bundle had rubbed against the top of the cover sheet, cutting through the tape and wearing into one of the wires. When I managed to separate the wires, as a couple were stuck together, I found that the worn wire had actually melted for about 4". It looked like a sausage when it splits open. The yellow insulation had curled back and melted to an adjoining wire, but luckily didn't short it out. Following the melted wire, I found it had been cut and joined to a short piece of green & yellow earth wire which went to one terminal of the low air buzzer. Which doesn't work. As the wire has been cut, I'll undo it and slip a length of heat shrink over the split section, then retape it and reshape it so it can't rub again.
While there, I checked with the multimeter and when the ignition is switched on, there is 12v to the buzzer. I ran a wire from the other terminal to ground, but it still didn't buzz, so I have to pull the whole circuit breaker panel out to get at the back of it. I'll get the damn thing working sooner or later, then work out how to disable it if it annoys me.

Something I forgot to check was the side clearance lights. Looking at the circuit diagram, they should connect to the 4th circuit breaker and come on with the Tail Light switch. May be an issue there as the tail lights didn't come on when I flipped that switch, but it is one of the things the previous owner has played with. I also noticed that there was nothing connected to the top of the 5th circuit breaker, which should be the wipers. I know the wiper arms are in a bucket on the cab floor and the drive cable is unscrewed above the windscreen, so there will probably be some work there. Something I noticed on the circuit diagram is that it shows both front and rear width lights. I don't recall seeing rear width lights on any of these trucks. I'm not even sure where you could safely mount them. Maybe it was an option that they later dropped. I don't have the actual Workshop Manual for the F1 & F2, just the RPS and Technical Manual.
As for the brakes, I did some more reading and found something. The MK3 Workshop Manual mentions filling the cavity behind the rubber cap in the pic below with Girling Brake Grease.

I searched the net and found a few mentions, unfortunately they are contradictory. One said it was a type of red rubber grease. Another said it was a type of Moly grease. A third said to use Girling red grease but never Girling white grease. The little bit of grease I found in one of the cavities was black and almost dry. It looked like Moly grease, but I've never seen Moly grease dry to an almost solid paste.
What I am finding after removing the drums is that some of the pistons that push the shoes apart are not sliding back in freely. The ones on the adjusters are even worse. Some of those I have had to tap back in with a drift and hammer before they would allow the drum to turn, even with the adjuster wound right out. If I have to, I'll pull them all down and clean/lube everything, but if I can get away with just repacking the cavity with grease and working the pistons in and out a few times until they are all lubed up, I'll do that.
Oh just remembered. I found this thing under the seat. I'm pretty sure it's off the truck somewhere as the bullet connectors match others under the dash.

It looks like a position switch, similar to what would be on a handbrake. Can anyone identify whether it is meant to be part of my truck or not? The end seems to be broken off and I can't find any numbers or letters on it.
Greg.