Aphids, hard to stop.

[kiwi]

Hi all,
I have a few broccoli plants in the garden coming along quite nicely. I've notice around the head of the plant where the new leaves are forming in a tight bud a colony of blue/grey aphids have set up residence. Ive tried spraying them with fatty acid, soap based spray and also a pyrethrum based spray. Neither have any lasting results. I guess the sprays are not killing all the aphids as the bud of the plant offers the insects good shelter from the sprays. They can get right in there.
Any ideas how I can destroy the whole colony in such a tricky location?
I'd like to keep treatment organic if possible.
thanks.

[wafflycat]

There's these - can't say if effective, as I haven't tried them.. but I am considering the tomato leaf one.

Organic Aphid Sprays - Two Homemade Organic Sprays for Fighting Aphids

There's a different garlic one here..

Organic Aphid control !! - Silkysteps - Early learning resources and childcare activites for the early years

[2dogs]

try these
Defenders - Safe Effective Natural Biologist Pest Control for Gardeners