Whilst it hasn't been officially confirmed yet it is looking very likely that Sonisphere is cancelled this year, Queen have already confirmed this on their website and BBC are also running a story. This is of course terrible news for fellow KISS fans, but I guess it's just a case of wait & see with regards to any other UK dates, although with a US tour coming up that isn't looking likely. The BBC site has the following:

"Sonisphere festival has been cancelled
Queen confirm Sonisphere festival UK 2012 has been cancelled Rock festival Sonisphere has been cancelled according to the official Queen website.
The event was due to take place at Knebworth Park, Stevenage on 6-8 July.
Queenonline.com issued a statement which read: "It is with very heavy hearts and much regret that we announce the cancellation of Sonisphere Knebworth 2012".
Organisers are yet to confirm the news officially, but hope to have a statement tomorrow. "