Stalling In 2009 Powershift

[SBM]

Sunday night car started stalling after being stationary then pulling off. First few times started again easily but then with wife and kids in car late at night it stalled and would not start. I had all electric but dead ignition, wouldn't even turn over. RAC guy disconected the battery then reconnected and it started first time! RAC guy recons that it could be that the immobiliser kicked in as maybe there is a fault in the key and disconnecting the battery refreshed the ECU?? Can this happen whilst engine is running?

I have had problems similar to this in the past but lost all power. I changed the battery (Bosch) and all was well. Then started happening again were power cut out but this seemed to be a loose clamp on the battery. Current problem is different in that I had all power but no ignition. Car seems ok again but I have lost confidence in as problem is so random. I am using the spare key on the advice of the RAC guy. I am going to take it to a garage this week but thought I would post the problem on the forum and see if anyone out there can help. Thanks.