I've listened to 1, 4, 12, 8, and 9 and they are all horrible music. Densely scored, unmemorable tunes
nah....he is more like Mahler in this than you care to imagine; what I mean is that he has got a limited number of tune-types/rhythmic types, and after that they are all only variations thereon - the last three movements of the Gothic, for instance, feature a plethora of tunes which are just variations of an unheard proto-tune based on the augmented triad. Mahler 8 actually uses a similar technique IMO. Which isn't a limitation in either composer - this constant protean metamorphosis is part of their style, and it is a mark of the deep-rootedness and genuineness of both composers that their music always sounds like them and no one else.
In any case, I would have no problem singing to you all the melodic material of the Brian symphonies I am familiar with. It's at its strongest, IMO in Symphonies 1, 3, 7 and 8, all of which are packed with wonderful things. The scherzo of no 3, in particular, proves that Brian could compose 'like every one else' when he wanted to.
Densely scored? Certainly, he has a distinctive juggernaut sound, those lurching marches, thudding chords and bass-directed textures; there is a deliberate brutal clumsiness built in - a typical Brian texture is a lumbering march destroying all in its path, and that no doubt reflects a deep and constant concern of his; there is little point in criticising its musical realisation, I think for it does the job it is designed for perfectly.
In any case, the scoring - study it - is an absolute model of its type. And when he wants to be delicate he can do it like no-one else. There are wraith-like passages in my favourite 8th Symphony as weird and delicate as anything in Berlioz.
(there is a nice folksy little violin solo in the beginning of the 1st - I say beginning since I can't get through the whole thing no matter how hard I try). The rest is a mixture of salon music, noise, and bits and pieces of Holst and Shostakovich but showing nowhere near the maturity or skill of either one.
The 'nice folksy violin solo' is a marvel indeed, but seen by some as a big formal misjudgement - it stops the momentum of this huge symphony before it has really got started. Personally I think it is perfect in its place, showing us, before we expected it, the still flip-side of the intense, turbulent music already heard. This is a principle in operation throughout the symphony, possibly best seen in the Vivace third movement. It is also an early example of the juddering juxtaposition of extremes for which Brian is famous, and which in the 8th symphony audibly becomes the formal basis of the whole piece - militaristic music v. lyricism, both driven to ever wilder and more ecstatic extremes in briefer and briefer cross cuts. Wild stuff. But I digress.
It is a mistake, btw, to see Brian as relating to Holst and especially Shostakovich, his junior by 30 years. He is a very different figure to both. Mahler is actually a good comparison in many ways, but few other composers are.
I am sorry, I think Maro Polo sense a loser coming (the sound sucked too in all those recordings) so they cut the cycle before losing too much $$$.
The sound wasn't great. But as far as I recall, that wasn't the whole story.