Some interviews and radio ads I've found on Dysan's request:
BBC Radio One with Mike Read.
Leeds 82 (Brian and Roger interviews).
Boston 74 (US Radio 01-01-74)
and some Radio ads:
Lakeland 78 and Milwaukee 80. link
Honestly I never found them interesting,hope you'll enjoy them though,there might have been some more at home somewhere ...
Damn!!! I used to have the radio ad for when Queen were to play Providence in 78. I would record the ad's on a micro cassette back then. But that got lost in the early 80's.