In case anyone is interested in obtaining the Perry Como 4CD set Greatest Hits & Magic Moments that Ken Crossland tracked down in Crosbyana in the latest issue of Bing (a much easier challenge than tracking down "Susianna" on Ariel!), I was able to obtain it from the following website:
https://treasurycollection.com/
In addition to the 4CD set, they have the DVD he mentioned, Perry Como Classics: Till The End Of Time,
and another "Original Masters" CD which combines the two Christmas albums Season's Greeting from Perry Como/The Perry Como Christmas Album.
By the way, I took advantage of the offer to buy NEW unwrapped CDs of the 4CD set and the Christmas CD together for less than the price of the wrapped 4CD set, and they arrived safely and appear to be brand new.
I'm not sure whether they ship outside the US, but at least within the US it is a way to obtain the set without making a large pledge to a PBS station (although I do support my local station).

I didn't have any Perry Como on CD - I'm more of a jazz fan and tend to favor Sinatra, Bennett and Torme along with Bing, so this seemed like a nice way to fill a gap in my collection.

I have to say I was amused at Ken's comment that it "bears a title that would normally cause a serious collector to run a mile". It does sound like something K-Tel would be hawking on TV, but I trusted Ken's judgement regarding its contents and quality.