Yes the 82 exists, at least in Comet - and that's the only place it seems. As AAJ says, I believe it's a rebranded 80. It appears to be the exact same spec as the 80. Usual Comet/Currys stunt to dodge the price matching. A naive trick these days with so many places selling them.
Last weekend, Comet were asking £1500 for it. It now appears it's gone down to £1399, online anyway (http://www.comet.co.uk/shopcomet/product/457108/PANASONIC-TH-46PZ82B/tab/specification). I assume because of the 81 coming out.
I should have made the effort and looked at the detail on the tv itself to see if it mentioned the 80, but I'm sure it's as AAJ says.