Put car away in a dry garage with all systems ok and went away for 6 weeks. Came back and apart from giving the battery a bit of a boost car not touched. Started car ( instantaneous ) and went for a test drive. Indicators not working, no lights, no sound. Tested hazard flashers, sound ( tick tock ) but no lights. What can have happened? All other electrics seem to be ok. Since the flasher unit is making a sound in hazard mode I assume it is getting power . Rather than attempt a random investigation of the loom can anyone suggest a more focused approach. TIA.

1 Check fuses
2 Check earth points, could be corrosion.
3 .....will leave to someone who is good with car electrics

You could start by checking all earth connections that you can see in the engine compartment. Clean, refit, tighten. Check all fuses, pull out and refit them a couple of times. Undo all connectors that you can see, and reconnect (do this a few times).

What switches are you using? Sierra switches can suffer due to corrosion on the contacts especially if they have been wet. Try spraying with contact cleaner or WD40

when multiple unconnected circuits fail, it,s 9 times out of 10 an earth problem, as the lights , indicater, hazards are on the column switches, there would be the best place to look

if its the old lucas hazard switch, then that isolates the indicators when they are being used for hazards.
exercise [or exorcise!] the switch a few times, (yea I know turn it on and off again, but do it at least 10 times)

Had a similar issue last year and the fuse would blow as soon as the indicators or hazards were put on. Turned out to be the side repeater bulb had fallen out the holder and was shorting across the terminals! Lost indicators, horn etc though in the process!