The following is taken from the FAQ at the old Atavachron website run by Jeff Preston, was published around 1996, and is presumably written by Jeff. Jeff was in direct contact with Allan for a time, and was supplied with news straight from the horse's mouth:
While watching the movie Speed, I noticed a credit for "Alan Holdsworth" under Orchestrations/Soloists -- is that Allan?
Good eye, there. Yes, that does refer to Allan, but none of his contributions for the soundtrack actually made it to the final print of the film. Allan said that the film's musical director, Mike Mancina, is a fan of Allan's, and asked if he would be interested in working on the project. Allan did some work on an Alesis ADAT and gave it to Mancina, but apparently none of the material was actually used in the theater or video release of the film.