Apparently (forgot where I read this), in the move from HE to SE, Tannoy finally started using more "audiophile-approved" parts inside the Prestige line of speakers. The internal wiring is done in Acrolink copper, which is high-end cabling from Japan (in fact the supplied binding post jumpers are also Acrolink). I think they're using higher end parts in the crossovers too, though I'm not sure what exactly that entails. Not sure if there are changes to the actual driver and/or crossover designs.
The HE apparently stood for "Hard Edge", which IIRC refers to the drivers' surround (the SE versions maintain this same surround).
