'Alleluyas' was written whilst Preston was sub-organist at Westminster Abbey and first published in 1965. The following exerpt from the Liturgy of St James is printed at the top of the score:
At his feet the six-winged Seraph;
Cherubim with sleepless eye,
Veil their faces to the presence,
as with ceaseless voice they cry,
Alleluya, Alleluya, Alleluya, Lord most high.
The revoiced Trumpet on the choir is not the best substitute for a Tuba/Ophicleide, but it works fairly well, I think. Also, this certainly wasn't the first take, as it's so difficult to get all the little details right in this piece - I'm still not sure I managed it in the end! I hope you enjoy it anyway.