Midle seat alarm - 2017 Dispatch

I have bought a 2017 Citroen dispatch a few months back with 60K on the clock and recently I have a problem with the middle seat seatbelt alarm.

The alarm comes on unexpectedly, without anyone seating on the seat, and I can not switch it off, Even when I plug in the seat belt.  I looked for a weight sensor but I can not find anything in the seat, cable etc. Also, strangely the alarm goes off if I accelerate fast or when I do a sharp left turn. Sometimes it works and stops and sometimes it starts again.

Any ideas?

Take it to the garage and run a diagnostics test ,or try and have it disconnected, would be my thoughts 

I cant stand them seat belt alarms drive me nuts best take it to garage and get it looked at