There is a difference between body painting, make up artistry and airbrush make up. Although there are those talented individuals that can do all of them.
As Victoria rightly points out, courses are not cheap.
As for body painting, the Wolfe Twins (former world champions), and Alex Hansen & Lymari Millot (current world champions) are all in the UK and doing classes this week. they may be available after the 28th August as well.
Bella Vollen (former world champion) and Pashur will both be in the UK in October / November and I'm pretty sure they will be doing body painting classes.
You could Google Bibi Freeman or Juliet Eve, both of whom do classes and aren't too far from you, but be warned, one to one training is liable to run you to hundreds per day.
As you can tell from some of the threads in this forum, we took a lot of time, effort and money to get to the stage that we are. That means we don't come cheap. If you want the best (certainly if you want the best in the world), then money talks and everthing else is just pis*ing in the wind.