might not be any help m8 but i had this happen to me a while back
parked up my car, locked it via remote, went into the shops but when i came back out and tried to unlock the car it wouldnt work

got the car back home and tracked it down to a blown fuse, however i tried 3 more 20amp fuses and it just kept blowing
weird i thought as i hadnt been near anything for months
however put a 25amp fuse in there and its been fine ever since and that was over a month ago now