Starter motor or immobiliser?

So for a number of months now my hiace has been temperamental when it comes to starting/responding to the immobiliser being switched off. I have had to click the button over and over in order for the immobiliser to switch off and let the car start. I had road side assistance come out the first time and he said it was that. Fast forward through months of putting it off as it eventually starts and is an inconvience but not a priority and yesterday and today it just won't start. Battery is low on charge and starts when roadside comes and jumps it. He suggested it's my starter motor...he also said it could be my glow lamps.. I will get in, go to start it and I get a small amount of crank/ turn over like a tiny bit. And then nothing just a loud click when I turn the key. Any suggestions