Dankworth and Tracey's arranging are both very under-rated. Great craftsmanship in both cases. Check out the Dankworth albums originally on Fontana and reissued by Vocalion ('What The Dickens', 'The Zodiac Variations', '$1,000,000 Collection' etc.) and also the various Stan Tracey Big Brass albums (more difficult to get hold of on CD in most cases). Love the way in particular that Tracey writes for brass and its a shame that he didn't write much for bigger groups from the 1970s onwards.
There was a great TV broadcast of the Stan Tracey Big Brass back plus featured star soloists in around 1968/9 doing a Duke Ellington Tribute called 'We Love You Madly..' (the BBC re-broadcast it a few years ago). UK Columbia/Denis Preston also released an LP by the same line-up (although it was recorded separately at Lansdowne Studios and not at the BBC). The original BBC broadcast was notable for being the only known film in existence of Joe Harriott 'in action'.