I agree 100% as well, but I rather think that their US counterparts, who predated these bands, Chicago and Blood, Sweat And Tears, should be here as well. They were pioneers in the development of 'brass rock', which combined the aesthetics of blues rock with jazz- very progressive for the era. I know that Dick Heath is a particularly knowledgeable forum member on this area- he posted a lengthy list of bands that fit the 'brass rock' criteria.
All of these acts could be added under 'jazz rock/fusion' without too many complaints, but Keef Hartley's first album, 'Halfbreed', is a superb album yet more in a blues rock vein.
By the way, two Keef Hartley albums are newly available on Eclectic Discs; 'The Time Is Near' and 'Overdog'. Both are superb albums, even masterpieces, of the genre. Even so, it seems odd to me that Eclectic chose to start with their 3rd and 4th albums for remastering- I hope they remaster the whole catalogue!