Locked out - engine running!

[zipin]

Wife was locked out, went to thaw out on drive, started and shut door but not locked, 10 mins later central locking had activated. So cars running fans on full rear window heater on etc and can't get in. I thought easy, spare key in passenger side door under the little cover. Still no good as the car just didn't recognise the key.
Is it because the transponder/immobiliser is already in sync with the one in the ignition and doesnt accept the second key? Strange one this, anyway Green flag call out and they have the gear to drop the window a bit enought to get to the window switch with a wire rod and into the car. They don't know the answer why it happened but suggest new batteries in fobs......any idea what code button cells these are?

Thanks in advance I'll let you know outcome but it seems that leaving the car open, running and defrosting is no longer an option!

 

[zipin]

Seems what happened is she opens up, gets in and starts car with drivers door wide open but as she's turning the key in ignition she accidently blips the central lock button on the keyfob. Doesn't realise, gets out then slams drivers door shut which is activated for the lock position, rides over the latch and locks up.
Anyway spare key isn't recognised by the immobiliser because it's already seeing the one in the ignition.
Full marks to Green Flag as this is covered by her homestart, they get here in 15 mins and into the car using their special kit in under 2 mins. Anyway it was nice and warm for her getting in!