Buddleia Butterfly Tower - pruning advice

hi guys - as per the pictures, I have a couple of Butterfly towers in posts. they're a smaller variety apparently, so pots are fine
this will be the third year I've had them. first year was a lot of flowers. I pruned them quite hard last year in the spring and there was a pitiful amount of flowers. although to be honest, I pretty much neglected them over the growing season, other than a periodic feed and a good watering regime
as you can see from the pictures, they have put on an awful lot of leaves and are doing ok. I think! so, should I just deadhead them and give them a general tidy up, removing any straggly bits - or prune hard(ish) again?
thanks guys