Best Answer
There seems to be more new socket 1150 MBs available here in the UK than in the US which is odd 
Could be good or bad news dependant on how you look at it, if there is 4 Xs 4GB sticks you could get away with a MB that only has two memory slots which would allow for 8GB, plenty for most games but not so good if you like flight sims.
New board that only has two memory slots here support for the board here lists the 1866MHz RAM as compatible but please note that it will clock backwards to 1600MHz, no biggie as the i5 4670k memory controller has a stock setting of 1600MHz.
Refurbished board from Gigabyte here that will accommodate all of the RAM, Gigabyte homepage for the board here