BTW having just heard some Roland Shaw tracks and TBH it really sound like the original is running in the background while creating a little bit of overlay here and there
just listen to DAWN RAID ON FORT KNOX - it's just the original track sans mono-sounding-layer with a drum overlay
No offense intended, but that's ridiculous. What I'm hearing are two different performances. Different soloists, different parsing of the phrases. The trumpets, drums, and string sections are playing the same sheet music (or Shaw has a very decent by-ear reconstruction), but the two ensembles are playing it differently from each other.
Both are good. Barry's own "Raid" is easily definitive; his string section is really nailing it. Shaw's tribute was a strong substitute for the casual fan who wanted wide-ranging Bond coverage on a single LP.