Well, I am not sure yet, but I believe the dunlop calipers are interchangable, weather it's a XK, Mk2, XKE. The difference is definitely in the fingers for the handbrake: E-type and XJ fingers were longer so as to clear the rear subframe when they changed to independant susp, the Mk2 were shorter, and those are presumably the ones that fit the Healey.
Tadek