can I use baking powder in place of cream of tartar and Bicarb in a drop scone recipe?

[HeadFairy]

if so, what quantities?

Yeah - I don't think I ever use a recipe for drop scones (we would call them pancakes here though - Scots).

If you add together the amounts for the two you should get roughly equivalent amounts.

Or, since many recipes use SR flour - use about 2 tsps to 8oz flour ought to do it.