Dyson has been a great discovery although I was put off him initially having purchased the Chandos CD of the Violin Concerto when it came out in the 1990s (I later came to appreciate it). Completely enchanted by 'The Canterbury Pilgrims' when it was released, the ending of 'Quo Vadis' is wonderful and his Symphony a delight. I listen often to 'St Paul's Voyage to Melita' and quite often to 'Nebuchanezzar'. Happy there is something undiscovered but if it is early Dyson I doubt it will be of the quality of the later choral pieces but here's hoping we may hear it.
These are exactly my own thoughts about Dyson! I am just discovering how good the Violin Concerto is and the end of Quo Vadis with(as the booklet notes say) its 'affirmative sense of homecoming' is as moving as any piece I know - absolutely wonderful music.