Does my Corsa have an immobiliser?
Sorry to answer with a question but does your corsa have remote door locking? If it has the immobiliser sensor will be in the key fob for a standard factory fitted immobiliser, if you don’t have remote door locking but do have a strange fob on your car key ring it could well have an after market immobiliser fitted. Best thing is to pop up the garage where you have your mot’s done & ask nicely if they’d have a quick look for you. If the won’t or try to charge you get you cars mot’d somewhere else in future as they sound right b******ds.