"Little Bear" has the looks of a British Blue. With these looks he may even be purebred. More good pics are welcome, but I dare to say this already now.
Now, Chartreuxes may look similiar, especielly as they have sometimes been interbred. But unless you have some especial reason to believe him to be a Chartreaux the jury will put the majority of voices on BB. Much more common, and the looks too. Rounded head already on this young individual. I have home a poster with young Chartreuxes. They havent these rounded looks at all as yet.