Haven't seen him discussed here before. I don't know of many if any film scores other than "Loot", but his contribution to library music is incredible.
I grew up with this one. Edit: Can't get it to display.
Back in my multi-image slide show producing days, Mansfield was the go-to composer for high energy "stemwinder" opener music. He did a couple of olympic-themed KPM albums which were terrific sources to get an audience cranked up.
I'm half surprised he didn't have a bigger career as a film composer. Perhaps he enjoyed not being tied to a specific visual, and composing for music libraries gave him the freedom to cut loose.
P.S. -- just went to Itunes and under "Keith Mansfield" I found an album entitled "Ultimate Sports Themes." Cuts 10 ("Wimbleton Championships Theme) and 11 ("US Open Tennis Theme") are the same theme originally written for the above mentioned "Olympiad 2000" album.
Listening to some of the other cuts at ITunes, I had forgotten how much of his output was fairly mediocre "Funk" stuff. I gravitated towards his dynamic industrial themes and their highly atmospheric underscore variations, very little of which is available at Itunes of course.
Here's some other examples of the Mansfield I loved: