robert i have been a decorator for most of my working life and i do not know of any self employed decorators in my city (swansea) who work as one man bands that command the sort of money you are hinting at. there are a few older ones that have a nice car and a nice van but thats because they have worked hard all their lives not because decorating is a lucrative trade. I find i can earn far more ph cleaning carpets than i can decorating.
example
typical tce house two rooms knocked in to one, strip wallpaper , prep walls , line walls, paint woodwork and ceilings,
paper walls, now even if it took 5 days ( i think 4) how many people out there do you think would pay £600 labour only to have their lounge decorated ? . yet there are cc's on here who say they can do 5 or 6 cleaning jobs on rooms this size (30m2?) in a day . now at £3 per m2 i would rather do the carpets in two rooms this size per day for 4 days than decorate the same size room, its not rocket science if your marketing skills are spot on a carpet cleaner with very little training plenty of work and a little common sense can earn far more money than a skilled time served tradesman and thats a fact .