Alloy wheel stains - how to remove?

So by way of an update and to round off this thread, sadly nothing will shift the 'stains', not even the Devils Juice when used neat made a difference! It does appear to be under the lacquer and something that will require a full refurb, or more likely I will just live with.

On the plus side I have since picked up a absolutely mint set of Winter wheels and tyres, so this only something that I will have to look at for 7-8 months of the year now whilst my Summer setup is on.

I will say however that the Devils Juice is an otherwise a brilliant wheel cleaner. I recently had to clean up my old F25 Winter alloys for sale and there were various grimey black marks on them that wouldn't shift with a first pass of Iron-X or Bilt Hamber, but came straight off with the Devils Juice. I understand it is a totally different cleaning mechanism and not something I would want to use regularly, but as a once a season cleaner it saved me alot of elbow grease and gave an excellent result.