Since the question was about outside controlled airspace, it should be obvious that in Europe that is below FL195. Therefore I think we can discount the issues about directs above FL195.
Ah, but in it's infinite wisdom, the UK has large swathes of Class C airspace between FL195 and FL245 which at times isn't classed as such, but become classed as Temporary Restricted Areas. It's still Controlled Airspace (by definition), but in which only services from the ATSOCAS palette, such as Deconfliction Service, can be provided by civil ACC or military controllers.
Get your head round that one and the legalities .... if you can !!