So many lockdown related battery / non-starting issues on this forum, but I didn't manage to find my particular issue - so here goes
The car has barely been used for a year, I've had a dead battery during that time - which has been replaced, and also a new alternator belt (something chewed through one during the first lockdown!). So battery is brand new and has full charge (now have a solar trickle charger thing in place).
When trying to start from completely cold, press the ignition button once - lots of fairly random lights on dash and some random warnings - these vary each time. Crucially (and it took me a while to spot this) the glow plug light does NOT come on. Attempt to start car, engine turns over but does not fire.
I then turn off ignition, wait a little bit - turn on again, 50% of the time the glow plug light comes on - I wait for it to go out (pretty normal amount of time, about a second or so I guess - depends on air temp etc) - and the car starts perfectly. Everything runs just fine. Subsequent starting and everything is fine.
I've visually checked fuses, and all look good. I'm assuming the glow plugs themselves as ok - as they seem to work great once they are on (they are at least 5 years old tho). Battery shows full charge (and car has no issue turning over).
Feels like an expensive annoying electrical issue - but does anyone have any idea on things I could check before biting the bullet and getting an auto electrician out?