I’ve now had the opportunity to listen to the whole of Led Zeppelin III test pressing. I can see why Jimmy Page rejected it! As well as the treble dropping out of “Immigrant Song”, the same problem occurs part way through “Since I’ve Been Loving You”. Also, the whole LP (both sides) has a different EQ balance to the final master that was approved, A5/B5. Obviously, with this test pressing being A3/B3, Page was also not happy with the next version either! I can imagine his frustration at having to reject A4/B4 too…
As previously mentioned, the only known test pressings of Led Zeppelin III (2401002) were A2/B2 versions, no other known copy of A3/B3 has ever been documented as being sold on the open market (nor A1/B1 and A4/B4).
Just how many copies of A3/B3 were pressed? Given that Jimmy Page had the final approval on the band’s sound, maybe just one copy was pressed for his personal approval…so perhaps this was the only copy and was once owned (albeit briefly) by Page himself. Perhaps he then returned it to the Polydor pressing plant in disgust! My guess is that in subsequent years, someone at Polydor had a ‘clearout’ of white label test pressings and simply gave a batch away without knowing or caring what they were…we’ll probably never know. But I bet you’ll never find another one of these…