Me too! I moved here just after they'd pulled out of the UK unfortunately...
So, we now have official word on the distribution, seems I was wrong about SpaceNK:
"We can now reveal that it's going to be available from July at Boots stores, boots.com, lookfantastic.com and ASOS.com. Then from September it will go into Selfridges, Harvey Nichols and House of Fraser."
EDIT: It's reached Boots.com already
http://www.boots.com/en/Boots-Brands-A-to-Z/Stila/?cm_re=c9095_rot2-_-product_list-_-stila_new_to_boots.com&cm_sp=cat_beauty-_-c9095-_-c9095_rot2