Hi guys and girls. Bit of an urgent one this

My car is stuck at home, i somehow managed to get it started again and drive it home from the local shops....

Car wont start. It says it needs to be in P or N before start. The car is most definitely in P. I would move the gear lever all the way to S and back up to P and still same thing.
The screen goes all fuzzy if i just try to force a start and sounds like its a bit low on battery. I have an ammeter and the volts stay conistant at 12.5V and do not drop.
So im thinking... either there is an ECU issue or the battery dropped a few cells which cannot be detected?

Has anyone had this or heard of this issue. I have the car booked in and to be towed next Wednesday but it is a long time as its been in my garage since last thursday.

ANY assistance is greatly appreciated.
It is a 2011 stock standard R.

Thanks