Thank's for all the input guys, problem solved I'm pleased to say.
Friend of a friend is ex Alfa service techy (amazing what you can get for a bottle of JD wink )
These were over the phone instructions.
Remove battery and fully charge.
Replace battery as normal.
Turn ignition on (just so dash lights come on)
Turn off again.
Remove the NEGATIVE lead from battery terminal.
"LEAVE OFF FOR 6 TO 9 MINUTES (deffo not more or less)
Replace negative wire
Turn ignition on with master key !!! and
Hey fecking presto it works.
Aparantly the master chip will re set itself, basicaly you have confused it into thinking that you are putting a new battery on. From what I can gather Alfa dealers have been skanking folk for years doing this, they have been charging a fortune for just simply doing the above procedure
Again thank's for the advice.