Grateful Dead t-shirt from 1947 has broken records at an auction in Sotherby’s.Up until the auction, the all-time record was held by a Led Zeppelin t-shirt from a 1979 show at Knebworth, which was sold for $10,000 (£7,275) during an eBay auction in 2011.In a new auction at Sotherby’s that record has been broken as the Grateful Dead t-shirt sold for almost double that at $17,640 (£12,833).According to a report on Defunkd, the t-shirt comes from the collection of Dan Healy, an engineer who once