I’ve fitted this “fully finished” skirting around the house but now I want to paint it. Can I just paint over it with a satin paint? Or do I need to sand it first so the paint sticks?

https://www.wickes.co.uk/Wickes-Ogee-Fully-Finished-White-Skirting---18-x-119-x-2400mm---Pack-of-4/p/284238?gad_source=1&gclid=CjwKCAjwt-OwBhBnEiwAgwzrUk56-wH0cJAu0qhAim0HIfkFOqbIzyWu-gZjtFKT0Kr-NNP0I4K2GxoCz1EQAvD_BwE&gclsrc=aw.ds

Anyone got any idea how to sand the skirting easily, I’ve got a whole house of this to do, I have sanding machines but was thinking the grooves would be a pain