I have a couple of lavender in big pots outside my front door, but they
haven't been watered as well as they probably should. They've been there
for 2 years and they didn't flower very well this year. (they don't get
an amazing amount of light, and I'm terrible for remembering to water,
and being by the front door they don't get much natural rain, on the
rare occasions it bothers to rain atm!)

I've just chopped them back quite a bit tonight (got to love the
gardening in the dark process at this time of year!) but they are ...
straggley looking and quite woody. How far should I cut them back? I
don't want to kill them, but if they're only going to perform as well as
this year (or worse) it might be better if I chuck them and get
something new for next year.

Any advice from lavender experts appreciated (other than "remember to
water them occasionally!" - I already got that one!)

Thanks