Your EKA code should be on a card that came with the handbook. It will be 4 digits and is different to the radio code. If you cant find it take your log book to your local Main dealer and he will give it to you.
well it turns out it wasnt the battery (100quid down the drain) it was a wireing problem to the starter motor !!
put it in my local garage to be fixed , all sorted , had it fully serviced while in there (total cost £665...ouch) but its running like a dream now , what fantastic motors thse are