Yes, Ray Steadman Allen has scored the David Willcocks fanfares and descants from the Carols for Choirs series and are published with permission from OUP by Rosehill Music. My own personal view having played/conducted a few of them is that maybe they're overscored in band terms. The fanfares and brass accompaniments to the descants that Sir David Willcocks wrote was originally scored for 8 piece brass (4 trumpets, 3 trombones and Tuba) and to my ears, sound a little overblown on a brass band. Having said that, the RSA conversions of the Willcocks descants are certainly a useful addition for band/choir Christmas concerts and the like, but the fanfares to Hark the Herald and O Come will need a fair bit of work for a lot of bands