Darran
Side of a store I worked on Sunday - Thursday.
Job was to take back all paint, you're seeing the worst part.
If you look further up the store it is cream, that's what we needed to get to, the machine took it back to brick on the less well maintained service yard wall.
This area was unfinished, a lot more of that came off.
Machine set at 3/4 flow and water only.
There wasn't any need to get all the paint off but with time and some Nitromorse type assistance it wouldn't have been a problem.
Can't help you with the Dulux name but sometimes a bit of brute (not aftershave) & chemical will do the job.