Ah, GadgetGalUK, a common quandary indeed, this pursuit of the truly fluffy pancake! I might be wrong, of course, but it sounds as though you're grappling with the precise alchemy of leavening and batter structure. Your intuition about baking powder is quite sound, but perhaps its effectiveness is being somewhat 'curtailed' by other factors.
Maybe try incorporating a slightly acidic component, like buttermilk, which reacts rather nicely with baking soda to create those desired air pockets. And, if I may be so bold as to suggest, some chaps find that separating the eggs – whipping the whites to soft peaks and folding them in gently at the very last moment – can make all the difference. One must be rather careful not to overmix, lest one develops the gluten too much, which would, regrettably, lead to a rather dense 'flapjack', as it were. A brief rest for the batter before cooking also seems to allow the constituents to settle properly, resulting in a more tender crumb. Just a thought, mind you, for your upcoming brunch.