Dreaded no start

[Ozruss90]

Need some advice please. Come across the No Start issue, a couple of times recently. 1st time, I started the Z at home as per normal, drove it into town to a shop to get some electrical work done. Got a call 20min later to say they couldn?t start the car. I went back to the shop and the car started ?? 2nd time, Started and drove to a meeting point prior to going to a car show. Turned it off, and 5 min. later wouldn?t crank. All ignition lights but no crank or click from the solenoid. Push started and went to the show. Car parked at show for numerous hours and started up fine to come home. Tried once home re starting and no crank.
It appears that it will start every time when cold, but once it has some temperature, it fails to crank over
Clutch switch bypassed, Starter relay added .
1990. #2774

Cheers from down under.🇦🇺
Russell