From the official fan club site, as part of the promotion for his new book:
http://www.rockyhorror.com/history/21qu ... harman.php
This bit was interesting, with the local reference:
Shock Treatment was going to be shot in Austin, Texas before circumstances intervened (a strike, availabilities, clashing schedules, etc) and we did some research there before we had to scamper back to London and shoot it in a studio - otherwise it wouldn't have been made at all. In Austin, the costume designer, Sue Blane, went supermarket shopping and many of the clothes Sue bought are up there in the finished film and many photos taken by the production designer, Brian Thomson, influenced the design of Shock Treatment.
A bit curious also because I've heard Sue Blane speak in person and she said they were scouting in the Denton, Texas area and that the second hand stores she got all of the studio audience's clothes from were in the Dallas/Fort Worth area. *shrug* It's amusing either way - Sue Blane basically just bought boxes and boxes of random second hand clothing that was later shipped over to London. She wanted the studio audience to look like authentic Americans.