If you are near manchester, then this chap is in stockport, so will come out to you. I have a 156, which is a code 3, I believe. He came out, cut a new key from a blank, removed the access codes unit from the car, programmed everything up, replaced it all, and I've been using the new key ever since. From memory, he charged about £130.00. Mangoletsi wanted over £300. If yours is a code 2, it's prob cheaper. Anyway it's ASTON'S ACCESS. AUTO LOCKSMITHS. Call Chris on 07966 207224.
I have no connection with him, other than being a satisfied customer !