The quotes I'm getting back are getting close to £400, which is way to much IMO. I am assuming its has to be a Stop Start AGM, I cannot seem to find a 90Ah one, only 80,85, 110 etc. Any suggestions? Also can I just pull out the old battery and change it for the new one the code it in? I do not need to worry about the battery being disconnected, radio being disabled or messing up any of the computers logic?