In this talk I will discuss 6d gauge theories that arise as a tensor branch deformation of superconformal field theories and determine the global structure of their 0-form group, including the possible presence of abelian factors and R-symmetries. This procedure allows to determine the global form of the flavour group of 6d superconformal field theories. With this knowledge I will discuss torus compactifications with a non-trivial flavour bundle which yield new infinite families of 4d N=2 SCFTs.