Starting issues

Bought a land rover with a Dicovery 300Tdi engine with auto gearbox. About 3 months in it wouldn't start. There was nothing, pressed the button and not even a click. Got the test meter out, Battery fully charged, starter button working, relay fine and when the starter button was pressed I was getting current to the starter solenoid. So, everything fine up to the starter motor. I swapped out the starter motor for a refurbished one that came with the vehicle when I bought it. After fitting the replacement - first attempt to start, nothing. Second attempt there was a click. Third attempt engine started. Tried again just to make sure and it started again. Four weeks later having not used the vehicle, same problem. Press the starter button and nothing, not even a click. Again, checks reveal everything fine up to the starter solenoid. Give the motor a thump with a lump of wood and on the next attempt I get a click but then nothing again. It would seem I need to buy another motor but before I do is there anything that I may have missed? Does it make a difference that it has an auto box? Can anyone think of what else it might be? Grateful for any advice. Forgot to mention, the start inhibit switch is disconnected to enable it to start in any gear so this isn't a factor.

You 100% sure your battery is good? Try a known working replacement

Yeh, first thing I checked. Battery has plenty of power.

I'd personally take the starter off and strip it down. If it came with the car, how do you know it had been refurbbed properly? And have you tired stripping down the one that came off the casr when you swapped them? If you can sort one out you could sort both out, and then have one and a spare!
Here is a really good article with pics on how to refurb one, and it doesn't look difficult at all.
https://www.landroverblogger.com/starter-motor-repair-replacement

I think I'll bench test the one that came off and remove the one I fitted and test that also. Not sure what I'll do if either of them work as I can't find a fault anywhere else in the system. Both starters worked fine and then just didn't. I guess I'll go through every inch of the system again.

DOH!.. Okay, along with my starting issues I also had some serious (noisy) issues with my auto gearbox which I have also spent weeks trying to diagnose. As I said above I removed the second starter that I fitted and tested it. It was knackered. I bought a new, third starter, tested it and it was fine so fitted it. Engine started on the button but my gearbox still sounded awfull. Tried to move the vehicle but it was very reluctant to move. Switched off the engine but it started to run away. I covered the air intake to stop it but still kept going then a penny the size of Denmark dropped in my brain... the starter was still engaged and spinning! I slammed my hand on the starter switch and pushed it down and the engine stopped. The starter switch is a momentary toggle switch but it was faulty and wasn't turning off. The first two starters had failed because they were running with the engine and basically just got cooked. The wails of pain from what I thought was the gearbox was actually the starter trying to keep up with the engine as it was revved. This time the starter survived so now the car starts and the 'gearbox' sounds er, like a gearbox. I can't believe that A. I was such a dunce and that B. that it was a cheap 3 quid switch that was the cause of so much trouble, a switch that I had tested for electrical function but not mechanical.

Glad you eventually sorted it!
Sorry it was such a tough learn!

That happened to a lawnmower i was working on once. I was watching it ‘run’ when the relay caught fire and the starter started pouring smoke. Penny only dropped then for me.