Immobiliser problem

[Busybee84]

Hi, first time here, apologies if this is in the wrong section etc

Have a 2012 Chevrolet Orlando with immobiliser issue. At first the immobiliser light was showing on the dashboard whilst driving, you could stop turn off the engine and restart and the light would be gone. After a week or so the car starts not turning over when the key is inserted into the ignition, now its almost every time you try and drive the car.

Took it to my trusted garage who said they cant do anything as Chevrolet have withdrawn diagnostic support to the uk, also rang Vauxhall who deal with Chevrolet and they said the same thing.

I’m now left with a car that is taking 6/7 times to turn over and I’m worried at some point it will stop altogether. It’s come at a really bad time as other half starts jury duty the week after next in a city an hour away!!

Currently awaiting a call back from Chevrolet themselves on how to proceed but prob wont hear until Tuesday.

Any simple/cheap ideas of things to check ourselves? Have looked at diagrams for fuses for the model but doesn’t show any label for immobiliser-does the immobiliser have a fuse? If so what else might it be labelled under? Might it be the battery? (Battery is likely 9yrs old) how would you check the battery? Ive also read that sometimes the immobiliser can get “out of sync” and something about removing the battery wires waiting for a few minutes and re attaching?

As its probably obvious I have no technical car knowledge but with the garage saying they cant help I’ve got a expensive pile of metal sat outside that i really need to try and see if i can figure out the problem with!!

Any advice or guidance appreciated!