2.0 remote key won’t unlock the car

[T.Doyle]

Got a 2.0 (facelift) with the key that has 3 buttons on it.
Pressing unlock on key does nothing. So I manually turn the key in the drivers door, as soon as I open the door, hazard lights start flashing.
I am then unable to start the car due to, what I think must be the immobiliser…
I have replaced the battery thinking it might be that but I have the same issue with a brand new battery.
i have left the battery disconnected for 15 mins to “reset” - no fix.

if I “quickly” turn the key to start engine, I hear a single crank but then now start. I am then not able to to turn the key to position 3 to attempt to start engine unless I remove the key again.

Any suggestions here? The key flashes red when I press the button to unlock

 

[T.Doyle]

I’ve just performed what I think is a key recalibration, : key into ignition whilst hazards are flashing, then pull key out, simultaneously hold unlock and press lock 3 times. The key then does long red flashes after this procedure but alas.. no improvement on my situation !