Used the power of MS Paint to try and figure out how to wire in a horn, foglight, reverse light, 12v socket with on/off switch, volt meter to replace the ammeter, temperature gauge, and rev counter (just for fun!) into the Austin...
Wiring fries my brain quite honestly, but I think this should be safe and fairly logical.
Everything is switched live and utilises relays with feeds direct from the battery.
The original fuse box has two glass fuses, one 35A for the rear lights, indicators, wipers and heater, and one 50A for the horn and interior light (weird but thats how they were...), and no relays other than the flasher box.
The main lighting circuit isn't fused (I guess bulbs would act as fuses if something goes wrong)
I'm replacing it with a 6 fuse box with two spare fuses. Two as per the original fuses but lower amp rated because a 50 amp fuse for the horn is mental, an additional fuse for the front and rear auxiliary lamps, and an additional fuse for the gauges, interior light, and 12v socket.
I could use one of the spare fuses for the main lighting circuit, but I will just leave it as is.