If you are experciencing this fault then the drivers / paasengers door locking module will need replacing.
Same thing happened to mine , mine started unlocking every now and again , got worse until the point it didnt unlock anymore.
And would constantly click to try and lock going at slow speeds , the anti hijack program trying to lock the doors.
Its quite an easy job to change it over but fiidly to take the lock out , i sourced one from a breakers for about £45 , a new one would cost around £140.
Fitting would be about an hour so add on an hourly rate of a dealer on top.
No
coding is required , so if they say its needs to be coded they are talking rubbish and trying to rip you off.