Starter Motor Click

Hello everyone...after reading and trying out all the various remedies on what could fix it but still nothing, i recently changed the HP fuel pump, removing starter motor in the process, battery disconnected too (car started fine before this), I read about the starter motor rebuild kit, did that too, so car has been stood for 3wks, put it all back together, reconnected battery and, with an excited smile, turned the key aaaand CLICK! Thought the battery was drained so got a new one...still clicking, I am finally at the end of my tether with this issue now. I’m no good with electrics or diagrams...can anyone shed any light as to why, after all this the damn thing is clicking, could it be a relay or would it not even click if so?

Presumably you've not wired the starter internal properly, after fitting the solenoid kit.

I think it is...I mean, it was put back the way it came apart.

You put a different battery on, but it's it charged? If you can, measure the battery voltage while you engage the starter

It was a new battery (I know, they should be full), but even with a battery booster/jumper attached it still just clicks.

Did the same a few months ago.
Turned out to be the small spade connector needed the crud cleaning off it to make a decent connection. Once disturbed and refitted it would seem not exactly in the same position.

Have you tried tapping the starter motor with a bit of wood whilst some tries cranking it ? I did this to mine after it just clicked on the petrol station forecourt after filling up. It started first time so I ordered the repair kit but ended up just cleaning up the contacts inside & it's been fine for the last 15,000ish miles !