Series 3 clickety click and not starting ... what's that thing called Help!

Folks,
I need a little advice with an intermittent starting püroblem.
Turn key .. clickety click sound .. no action.
Open bonnet check cable to starter solenoid all ok ...
check cables to that (thing i cant name) where the battery cables conect to ...they seem (look) fine

Still no starting joy and now the lights are not working ... eh!
Second check of cables ..

Oh now it works .. ??

So could this be bad connections on the back of the key?
Bad earth on the same circuit ..
Or that thing that I cant name being at fault .. what is that thing? A solenoid?
I cant upload any photos as all of this happend at 5.30 am on my way to the station.

Simon

I should add that sometimes there was no click but the dashboard lights just dimmed and whent out ... this is why i think it's an earthing thing ...

Are you sure the battery is good and the battery connections are good at the terminals. It sounds like a loose battery terminal connection.

Col

Yes the battery is relatively new but i was wondering if a bad starter solenoid would cause the same effect, i'll take the cables off and give it a good clean tonight.
I just looked and such an item is about a 10er on Paddocks

The only issues I have had like this was one of the big spade connections on the back of the key switch. It didn’t click or dim, it just went dead. A clean and a squeeze with pliers sorted it.

if you have a drain on the battery it won't matter how new it is. disconnect and/or charge the battery overnight

sounds like low/flat battery symptoms to me

Short the two large terminals on the solenoid to see if starter motor turns if so your problem is on the supply to the solenoid coil.
Alternatively connect a wire from the supply side of solenoid and touch to the small spade that the supply from ignition switch goes too.

Battery.

OK SO ... the worst place to try and gain access on a SIII is?
The birds nest behind the instrument panel ... following advice here checked the terminals from the ignition switch . no change.
Part two was to take of the leads from the solenoid and give the ting a good clean with contact spray, checked the feed wire to the starter, couldn't check the starter as Blackburn suggested as i have a new (closed) starter
Success ... seems to have done the trick .. we will find out at 05:00 when i (try) and leave for the drive down the mountain to the station

( i still think the 10er for a paddocks solenoid might be an idea -this one looks like its 30 years old)

All good ... starts no problem....

excellent