My 2011 multi jet door open warning on dash is permanently on , the rac engineer said the test he did shows a 0.7amp drain and it's killing a new battery had to jump start .Does anyone have any ideas please as I'm reluctant to use car as I don't want to get stuck in a car park etc .

Although what is described is a Punto, I'm pretty sure it's the same for the Doblo.
https://www.fiatforum.com/punto-ii/335907-door-ajar-switch-sensor-location.html

Hi ,this might be useful to all ,the rubber flexihose in the rear door taking the the heated rear win cable rear plate lights and door sensor had a break in the cable going through the flexible . Bit of solder and heat shrink job done...