yes I lost all my music etc. How the hell did that happen? Well after having a cuppa tea I figured out what happened after speaking to an Apple genius. They really deserve their names! What the root cause was is simple. When I first created an Apple ID I used my now discontinued Ymail email. However, as I’m a subscriber of MobileMe i also had a sort of Apple iD which I activated fully when registering my iPhone on iCloud.
So when I logged on as my new Apple ID all the other stuff was missing. So I had to log on using my old ID, authorise my new MBP and then use the new ID. Bit troublesome but to be honest I can live with that. Puh am I happy to have recovered all of my beloved stuff.