ah well was going to send you one of my keys but fixed it myself. Came across you mentioned/recomended several time's.
Took me a few hours to discover that the damn immob chip is not on the circuit board
You can sometimes buy empty key blanks on ebay. You get the blade cut to match your existing key, then transfer the guts of the old one to the new keys housing. Including the small immobiliser chip.
Alfa should also sell them.
timpsons will make you an uncoded copy for £6, then you need to grind it down so it will fit your key. to reomve the snapped part you need to drill the round lump of plastic inside the key, then you can glue your new one in place. its a lot easier than i make it sound.