Boozyuki is right in that the European leg is set for 30 dates. That leaked itinerary had a second Twickenham show on June 19 listed all along, but no other additional UK dates. All the other privisional additional dates in Europe already account for the 30 contracted shows.
Now that's not to say that TNA, the promoters of this tour, will not contract for say another 5 shows to be squeezed into Europe, but I think they will have to negotiate this now with U2. As a result, I would not continue checking with Ticketmaster online for additional dates in Manchester, Glasgow and Cardiff, since if they do extend the European leg beyond 30 dates, it will take some time. Perhaps they'll be able to sign the contracts between TNA and U2 quickly and have them announced and on sale as soon as next weekend, but I certainly would not expect additional UK dates before then, if at all. They will do a public announcement if additonal shows do get contracted.