Vauxhall combo 53 plate new key

My main key does not turn my van on now. Micro chip and key not corresponding. Spare key works.
Question : what do I need and where do I go to get my key working again and responding to the vans immobiliser or however it works

 

Where in Essex are you? If close to Colchester then I would recommend Keys is Us.

 

I'm not unfortunately, I am in Romford.
Perhaps I will take a trip to the zoo sometime.
I've read some post at that there are sequences with the ignitions and locks that you do to sync the key?

 

These are no doubt places in Romford similar. I have always found Keys is Us excellent masses of key cutting equipment and seem to be able to reprogram just about anything to do with keys.