The ants aren't an issue, they're only there for the honeydew the aphids excrete, so treat the aphids, the ants will disappear. I've posted a link to RHS advice on treatment on your original question.

Sorry to have confused the issue, Bamboo. I've got to get out of the habit of assuming things are universal, just because they work that way over most of North America.

I'm just glad we don't have the range of ants and termites you do over there!