Orig. Rhyming Slang (UK), not necessarily only used by davids.
Back in the day when consumer electronics were very expensive, often needed maintainance/repair and we were poor, Radio Rental was a large British company which rented... TV sets. (Doh!)
Often shortened to just Radio.
Vice City? Radio Rental mate.
Wow! Totally, like RRRRRRRRaaaaaaaaaaadioooooo RRRRRReeeental!
Shut it radio.