Decca were a bit inconsistent with the label names in their catalogues; in all the ones with numerical indexes that I have (1974, 1975, and 1976), all the PFS prefixed releases show the label name as just "Decca", whereas the WA, WAP, and WAPS are all shown as "West African", and I don't think that branding was ever shown on the record labels, only on the 45 sleeves. They were inconsistent with the CD releases later on as well - the mid-price Ovation range only showed that series name on the covers, not on the discs, whereas the budget Weekend Classics series had that name on discs as well as covers.
With a nod to keebrev, Gill Sans, PhilMH, added a couple of scans of the alternate Phase 4 explanation inner.
Discogs has the label on these Phase 4's as simply Decca, and has "Phase 4 Stereo Spectacular" or " Phase 4 Stereo Concert Series" as the series, rather than the label as we have, is that right?
(i think these Phase 4's sound pretty good, judging by the one's i've heard so far)