I always look in charity shops for BMX books - have yet to find one.
Regarding the CHiPS annual - many of you will be aware that there is a link to BMX. One of the episodes had a sub-plot featuring a BMX racer, with stunts by OS racer Anthiny Sewell. This is what wikipedia says about him:
"He did on screen stunt work for the BMX race subplot in an episode of the American television series CHiPs which originally aired on March 3, 1979. Fellow racers John George and Charlie Litsky also appeared. It was entitled "CHP-BMX" (Season 2, Episode 21)."