Electrical fault - S1 doesn't even try to start

[PhilBell]

After my 3.8 has been laid up for 10 months while I tackled other jobs, it now has an electrical fault it didn't before.
When I inserted the electrical cutoff switch and turned it, the low fuel light came on (it only has a gallon in there). But bear in mind the key wasn't in the ignition yet. When I inserted and turned the key, the submerged fuel pump (solid state) whirred busily then stopped, presumably when up to the 2psi I set on a new inline pressure regulator from Demon Tweaks, mounted in the pipe run between fuel tank and rear bulkhead banjo. Meanwhile, it filled the fuel filter bowl in the engine bay. When I thumbed the starter button, nothing, not even the click of the starter solenoid, never mind any attempt to turn the engine. I've tried running a separate earth to the engine in case it's developed a poor earth strap contact, though with the amount of oil coating the earth strap I'd be surprised if oxidation were possible.
In case you're wondering what might have been disturbed during the other jobs mentioned earlier, they comprised removing the camshafts to reset the valve clearances, removing the carbs to replace the jet diaphragms and changing the dynamo/water pump drive belt.
Anyone recognise the symptoms?

[caveman]

Phil,
I would firstly ensure you've a fully charged battery.
Then, I would bypass the cutoff switch by bridging across it. Try to start on button again.
If it remains lifeless and no click from starter I'd suspect starter or solenoid initially. You can tap the starter solenoid whilst (getting assistant) pressing start button to see if it jolts it into life. It maybe worth checking starter wiring too incase somethings amiss.
NB. I have 2 earth straps to ensure good earthing.

[PhilBell]

Update - despite my CTEK apparently going through its full charging process successfully, turns out the battery was at fault. My multimeter showed that the battery voltage dropped from 12v to 1v when I pressed the starter button, likewise when I switched the headlights to dip beam. Co-opting a battery from another car enabled cranking and starting.

[Gfhug]

Phil, as was posted in another topic, trickle chargers are good for a fairly sound battery but won’t charge up from really low. Whereas the old fashioned chargers do. If you’ve got one of those try that on your battery. I’ve certainly found the old style useful to have around.

Geoff