It's run at Scalford hall, once per year. Next one should be coming up in the next few months. I've been twice now, really enjoyed the shows. Great way to set context of what is possible, what do I like and how close am I to getting there already.
If anything, some of the best systems I've ever heard have been there.
For me the most enjoyable last year was:
1. The already mentioned Wilsons (not sure which models, but they were standmounts), as driven by a combo of Wadia, Modwright and Krell
2. Can't remember the streamer, but there was one running into an old pair of Meridian DSP6000s, which sounded fabulous, enough so that I ended up visiting several of their dealers listening to the newer versions, (DSP7000s).
Lots of other REALLY good stuff too, with everything from home built kit to all the genuine big names, e.g. Linn, Naim, Esoteric, Nottingham Analogue, VPI, Avant Garde, Quad, Rogue Audio, Audio note, Snell, Border Patrol, DCS etc.