Just de-lurking after to all this time to mention that I've discovered an eBay trader who sells pdf scans of
British trade catalogues. A lot of the dealer's stuff is from the 1970s, and would be fairly useful for anyone needing to research the nuts n' bolts - with prices! - of everyday life.
(Nostalgics would also get a kick out of these. There were some scans of toys from a 70s Argos catalogue that really took me back!)