I collected a sampling of the mealy bugs from the bush and made up a remedy. This takes a week to brew so by the time the remedy was ready to use the infestation was pretty bad. Before I treated the bush I gave the whole pot a blast with the steam cleaner to get rid of all the little beasties that were happily basking in the sun.
Step one - Relatively clean pot.
Mixed up my remedy into a spray and gave the whole bush an absolute soaking and poured the left over spray onto the soil.
Step two - Plant sprayed
An hour later the whole pot was crawling in mealy bugs. Now normally these little beasts are not obviously moving around, but they were crawling all over the pot. Interesting result, they very obviously were reacting to the spray.
One week later on very close inspection there are no obvious bugs on the leaves and branches except right at the junction of the leaves there are still a few there. It is hard to tell if these are still alive, I think they might be, but I am going to wait a while longer to see if they die off. The plant looks a lot healthier and just has a white residue on the branches that were smoothered in bugs.