Yeap, US based but in partnership with carphone warehouse in the UK.
Opening offers are good value (got a 50" LG plasma for £500, cheapest elsewhere is £700) but otherwise I found them overpriced compared to online. Service is so and so, nothing special.
If you are looking for opening day offers, its variable. At lakeside, they had 50 of the 50" LG plasma, 150 32" LCD toshiba both of which were still available at lunchtime. But only 5 of an AV amps (I think the one you are after). I queued from 5am, store opened at 7am and was around 15th in the queue but they were all gone.
Queuing system was very well organised, basically they had numbered leaflets for each sale item in stock and they walked down the line before opening time and handed out the leaflets so no crazy rush. I would advise getting there early if you want a specific item.