Hi again, yes the cost would be high at the main dealership for sure. After I purchased and fitted the new alternator everything seemed to be totally ok and charging the battery as it should. Then out of the blue about a month later the Alternator not charging the battery message appeared on the dash. I immediately contacted the supplier to ask how I would go about returning the unit thinking that I was seriously unlucky to have a brand new faulty unit. They came back to me immediately saying before I removed it check that the fuse was not faulty and sent me a video link to follow. The fuse was connected to a fuse box under the bonnet next to the battery. My car has the battery in the boot with the fuse box next to it in a side compartment, where the jack is stored. It's that information that made me aware that there is more to the problem than just replacing an alternator and the battery.