STARTING PROBLEMS-PLEASE HELP,GETTING ANNOYED

I have recently bought a 2001 316i around 4 months ago, ive had a problem of it taking 10-15 turns of the key to get it started, i get nothing except the dash lighting up as if the immobiliser is preventing it, ive had it back from where i bought it but to be honest their bobbins, the best they could tell me was code 140 "key 2 implausible"

I must admit the car is used very little and even when it is its short journeys

i have done some digging, is it true that theres a chip in the key which needs charging (which is done while in the ignition) and because its not being used its not got charge enough (i only have the 1 key)

Help with this would be really appreciated, i got rid of a belting problem free motor for this and its DRIVING ME MAD