Putting on Ex BBC hat here!
What Jim says is factually true.
Since the Mid 90's there has been a project to collate all the various recordings held by the Beeb. It started with digitising all the Peel sessions, followed by Andy Kershaw sessions, and then any Live concerts that still existed. It was such a success that a couple of years ago it was decided to archive the whole shebang!
Talk about painting the Forth bridge!
The only problem is what still exists. It's very true that when tape first appeared it was very expensive, and needed re-cycling. Normally this would be done by various producers, but, ultimately by an Archive panel, who decided what was and what was not worth keeping!!
So, Churchill speeches made the cut, but many other recordings went to the great reclamation site in sky. (Brooklands Park, actually.!!)

It was all a bit hit and miss, and I wouldn't be surprised if the Kennedy collection has bitten the dust as far as the Beeb is concerned. (Remember Acetate discs are not only fragile but very heavy in bulk!)

As far as tapes in skips is concerned, This came to light when working on the Nic Jones re-issue CD's. Having contacted the team that worked on Folk On 2 before it became outsourced to Smooth Operations , I was informed that having been wound up, there was nowhere to put the hours of recordings so.....the inevitable happened.

As an example, of the 8 Nic Jones Peel sessions, only 1 survived.

If you would care to check out the Peel Sessions book, at the end, there are 100 pages listing (as far as is humanly possible) every Peel session ever recorded. Dates Times etc, etc...

With about 25 bands to a page. Each band doing four songs or more. Well you work it out. Well at a rough guess, that's 100 times 100 = 10,000 songs.   And that's just 1 Programme!!!

Yes, I know that we're talking a rock programme, not folk, but it's a well documented example of the sheer volume of material that has been recorded over the last 80 years.....Anyone want to work out 70 years of Promenade concert recordings? Or Friday Night Is Music Night? or The Organist Entertains, ITMA?)

As to what has survived of the Kennedy collection. Who knows. The archive team (about 10 of them I think. not much of a budget!), have probably only just got into the 1930s.... So maybe they'll turn up, (whats left of them) in about 2040. Remember you have to play these things in real time!!!!

so, I look forward to hearing them on the other side of the veil!

Cheers Ralphie