I uses a similar concoction:
Though TBH diluted dish soap also works.
This stuff seems to be good too, but I only started trying it at the end of last season when my brussels had the usual infestation of the mealy cabbage aphid
It certainly helped with that.
The trouble with ladybirds is that even when there are lots of them (and there were, here, last year) they simply cannot control an outbreak of the mealy cabbage aphid. Ok this is partly because they are under netting to keep the local pigeons off - but even without netting they just cannot keep up with the reproductive rate of those nasty grey little fuckers. I tend to let green aphids be, on my beans, and the ladybirds mostly keep things from getting too out of hand.
