Clicking and intermittent starter motor turning

[Bremar 7]

Just a quick question maybe. The car always starts but the irregular click but no starter turning remains.  
Surely the Click is from the solenoid trying to engage the starter motor and so the problem is never with the Brown connector or indeed with the connection of the black wire to the starter solenoid (unless the car just won’t start). Not really thinking I originally launched into finding and cleaning the brown plug, but the issue persists. Surely the single click  is actually the starter solenoid kicking in so the problem must be elsewhere - say the connections inside the solenoid or the starter motor main connections or  the starter motor? Or am I misdirecting myself? 
thank you Bremar 

Edited 5 hours ago by Bremar

[PhilNW 67]

The red wire from the ignition switch to the starter solenoid has been a common reported problem.

 

Try running a jumper wire from the small solenoid terminal to the battery to check it turning over every time you touch it to the battery terminal