Story here on the BBC website about a party bus / traveller bus / rave bus (call it what you will). This is the type of thing (or worse) that people assume you mean when you say 'bus conversion' in the UK:
http://www.bbc.co.uk/news/in-pictures-34775283 (http://www.bbc.co.uk/news/in-pictures-34775283)
Jeremy
Interesting story but rough looking bunch. Although there is the pretty young lady in that one picture.
Immediately recognizable as a Daimler Fleetline, 30 foot body (don't ask me how I know). I would have guessed later than '69 but if it was in service in Cardiff in '69, that's what it must be. Probably rated to carry about 90 passengers in fleet service. As '69 or earlier, the chassis would have been made in Coventry (that was before the transfer to Leyland in the Nawth) but I don't have any idea about the body maker, other than it's not "Northern Counties" who built mine in '76 (but Northern Counties, based in Wigan near Manchester, made buses that were mostly used in northern England and Cardiff is in southern Britain).