Looking how they make the Mk, it looks like you maybe able to unclip the 2 way switch and fit in a Grid intermediate, , perhaps removing its white shroud first, or a switch from a 1 gang intermediate if they make one i have done similar with masterseal units.Except, the OP wants all of the switches to look the same....
However I have noticed Mks white stuff sometimes varies shade slightly so the two rockers may not match exactly