Starting problem

[Jelevents]

Hi all been having an intermittent fault with immobiliser not always turning off when trying to start, but will always start 2nd or 3rd time, tried spare key turns over but will not start at all, battery in key is new and seems to have started playing up after changing battery. 
So today started fine drove in minutes switched off and then would not turn over, just click from fuse box in engine compartment, tried other key nothing, tow started drove home now starts again but still not switching off immobiliser couple of times.
Does it sound like I need a new key or starter relay?
2009 1.6 hdi also has key error message comes up on dash
Thanks Jerry

[cancunia]

The battery in the key is for the remote locking, I'm not certain but I think the dash warning about the key is to do with the battery in the key. Also in the key is an immobiliser chip, it doesn't need a battery but is activated by a magnetic ring around the key hole in the steering column lock. Are both keys remotes?
To check if the keys are working with the immobiliser, you'll need Lexia or Diagbox, but to me it sounds like your main problem is with the starter motor as you've managed to tow start the engine.

[OMG]

Would it start at all (tow start) if the immobiliser was operating? Perhaps just a problem with starter circuit?

[Jelevents]

Update on starting issues earlier tonight refused to start again not turning over, gave the gearbox a whack and bingo it started so I know its a faulty starter but how can I clear the key anti theft fault, does it need a diag box?