Try rocking the car backwards and forwards, handbrake off of course. It could be that the gears could be temporarily stuck because of pressure on them caused for example by parking on a slope with the weight of the car being taken by the transmission. This can happen on a "normal" manual car and you have to give the gear lever a really good push to disengage the gears. Just a thought and maybe worth a try.
Hmmmm ....I've been working on the gearbox activation hydraulics power unit after getting a leak and disconnected the unit (without disconnecting the battery). When I fixed the leak, put the ignition on and the car is in drive. Will not go to neutral for any length of time. The system has been bled several times. Needs to go for a diagnostic check and reset (on a trailer as it wont start with being in drive). I thought someone said there was a quick release for the gearbox?
Ah it's more complicated than I thought. If you try to rock it you'll have to be sat in the car working the paddles. If it does go into neutral turn the ignition off straight away. that may stop it going back into gear. You might be lucky, I hope you are.
It goes into N when the bleed screw is open on the power unit which when ive managed to get it in N ive switched off but the car is still in gear the car is being picked up and will use skids to move it for diagnostic check.Fingers crossed a self learn after bleeding should sort it.