Hi!
I have just heard with much pleasure The Music of the Spheres recorded at the 2010 proms, a piece not entirely on the scale of Havergal Brian's Gothic Symphony but, including organ in the orchestra, a piece wholly enchanting and intriguing.
The concert was written up online at
http://www.telegraph.co.uk/culture/music/proms/7927866/RuedLanggaard-return-of-a-visionary-composer.html
and it's clear, the composer having been an organist that there are likely to be gems of repertoire in his ouevres.
Best wishes
David P
Imspl.org has two organ pieces by Llanggard - A Toccata in A and Fantasia Patetico