Lol,
There are some cheap-ish used copies on Ebay and AMZ. It is in the same vein as "Boult on Music" but all based on Brian's articles, selected and organised by Malcolm McDonald.
The chapters are as follows:
Intro - Havergal Brian, Journalist
1 - Spirit of England
2 - The Older Generation (Cowen, German, McEwen, Parry, Stanford, Sullivan)
3 - Elgar
4 - Delius
5 - Bantock
6 - British Music in Performance
7 - Nationalism, Leagues and Competitions
8 - Near Contemporaries (Bax, Coates, Coleridge Taylor, Davies, Dyson, Foulds, Balfour Gardiner, Grainger, Holbrooke, Holst, Hurlstone, Scott, Sorabji, RVW...)
9 - Younger Composers (Britten, Cooke, Goossens, Mayerl, Walton, Warlock)
10 - Orchestras, Choirs, Bands and the BBC
I skipped the Delius and skimmed the Elgar chapters, both of lesser interest to me but the rest is interesting so far (i am in chapter 8 right now) and it adds some more context to the music I have been immersed into in the last year or two now.
As per his intro in Volume 1, McDonald's plan was to originally release 6 different volumes of HB's articles in total :
1 - British music
2 - European and US music
3 - Conductors, performers and other contemporaries
4 - Great composers of the past
5 - More general music topics
6 - More autobiographical writings
I did have a look at Vol.2 before, available as well, but the composers were not of interest to me.
Shame it stopped at No.2. I wouldn't have minded Vol.3 and 5 myself.