The taller stems sound as if it was getting ready to flower. Did it? That's perfectly normal. Clip over the plants with your shears after flowering. You might want to do this in spring rather than autumn if you have cold winters. I harvest the flower stems for use in the kitchen.

Yes, they did flower (or start to). I'm usually pretty good at keeping the whole thing pinched back but towards the end of the summer I get a little lazy and it starts getting taller and trying to flower. I wont cut anything back just yet - I'll wait until spring.

Thanks!!!

Growing (Tall), flowering, producing seeds, in plants world that is "mission accomplished" in some cases.