I think that's Cambridge Chemists you're thinking of. They're also right down the street from the Penhaligon's store. And even if you don't plan to buy anything from Penhaligon's you should stop in there anyway. The sales associates are incredibly helpful and knowledgeable, you'll get a free chance to sniff every scent they make if you want, and they'll probably send you on your way with samples of your three or four favorites to try before you even think about buying.
in fact, the lady I spoke with in there said "oh heavens, don't buy anything today - here, take these to try out first. We'll send you a catalog later on."
Oh she also told me I narrowly missed meeting Tim Robbins when he stopped in for a bottle of Blenheim bouquet about 45 minutes before I got there.