I would put a small fortune on the fact they WILL come to the Uk, based on some Sherlock Holmes-style detective work...
Basically on the 'euro map' on HappySmurfday.com they show the UK. Now, if you remember the old website smurf.com (the official one) whenever they did tours/showed video release dates, they NEVER showed the Uk. They always cut it out of the map.
My inner-Mulder says that, if they were not coming to the Uk, then why would they have included it on a 'map of europe'.... or INDEED translate the page happysmurfday into ENGLISH?
Couple that with the fact that IMPS seem to be 'slowly' bringing the smurfs into the british market... sweets are now in Topshop and shirts in Urban Outfitters.
All signs point to good news... in my opinion!