thanks for the reply,
confirmed after getting audio info...
itunes download... first track on tron legacy (overture) - 256 kbps
recent CD rip ALAC... first track on abbey road (come together) - 819 kbps
DB power amp was one of first mentioned and came up a lot after a cursory look at options, it sounded like it stripped all of meta-data, but that still may be more direct route, even if that needs to be manually edited back in (replicates the stereo box set, about 225 songs on USB... all british albums, plus US MMT and two past masters volumes for the singles/non-album tracks) than some of the more byzantine, labrynithian ways.
The power amp preserves metadata in my experience. One of the modules is batch converter, find select top level folder you wish it to convert, destination folder and output file type and off it goes. You just mass import destination folder to iTunes and it should all be there. That assumes the Beatles stick allows access and the FLAC files aren't copy protected, which I strongly suspect they are. But the software is about £15 anyway and means you can buy legitimate FLAC files elsewhere of any music rather than CD and convert to ALAC.