Ticketmaster had a couple of O2 Arena tickets, 5th row Block 101 (raked section) a couple of hours ago. Gone now of course. Ticketweb are selling the £200 "Tour Package" ticket, there's a Row C Block A3 ticket in there. Ticket sales, all a bit of a mystery really. Thing is, like album sales, remasters, etc etc there's no one making you buy.
My tip would be to wait a while and keep your eye on things like TicketMasters Facebook and Twitter feeds. Previously I've got extremely good tickets within days of the event when something like "production seats just released" (or similar) notifications are made.