That Billboard linkiepoo is not working for me.
["]Try this](Billboard - Google Books) (I missed a closing quote on the URL.) Do note that that is not referring to “progressive rock” as we know it today.
Here’s the 1967 source using the term “progressive rock.” In the Google Books results, the snippet is: ““Progressive rock” is what the businessmen are calling the non-top 40 FM rock stations, and they’re beginning to smell money. Boston, Detroit, Philadelphia all have one or more “progressive” stations, and I’m sure they’re not alone (in fact, I’d …” which is where I figured out that what is meant by the term pre-King Crimson is apparently what we’d call “alternative rock” today.
I looked up both NME and Melody Maker’s reviews of Court of the Crimson King (Oct. 18/69 and Oct. 25/69 issues respectively), and the magic “p” word did not appear in either review. Then I looked up their reviews for the second album, In the Wake of Poseidon (May 9 and June 6/70 issues respectively), and still no magic word. However, the May 16, 1970 issue of Record Mirror in its review of that album contains the following passage: “The album has been impeccably produced and arranged and must rank as one of the most important contributions to progressive music for some time.” So it looks like Record Mirror wins.
Couldn’t find anything in the UK papers about “Wowie Zowie” that didn’t pertain to the Mothers of Invention song.