In all its minute details, Der Rosenkavalier is rooted in a painstakingly stylised version of Rococo Vienna that, paradoxically, is further fixed in a web of cannily juxtaposed anachronisms. Upset their balance and you risk upsetting the balance of the whole piece. That’s no bad thing, of course, but Richard Jones’s bold new production for Glyndebourne — opening the festival’s 80th season — shows exactly the advantages and disadvantages of doing that.