Micra K12 Auto - Stuck in first gear

I recently bought a Micra K12 auto, which runs great. There is one annoying thing which happens sometimes -the automatic gear box gets stuck on first gear and refuses to go up, regardless of the revs reaching 4-5k rpm! The temporary solution for me is to flash hazard lights, restart the car, and most of the time, it works! Are there any pointers to what this could be related to? Is it the gearbox ECU, or the gearbox itself or something else?
Hi mate.. ive got exactly same issue with my micra k12 auto.. did you manage to find a fix? If so what was the cause of this happening?
The switch inside the gear shifters sometimes go on auto boxes
As they wear over time and stop the car from being able to engage properly.
Probably not linked with this issue but its worth checking as this is a simple switch.