Has there ever been a succesful non-finalist?
 

To anyone’s knowledge has their ever been acts who didn’t make the final but go on to bigger things, maybe even several years later?

Ed Drewett (2014) has written singles for Oine Direction, Little Mix, Louisa Johnson and Jonas Blue
AJ and Chloe (2013) are/have been Strictly Pro's
Charlie Wernham (2008) is now an actor and has been in things like Bad Education and Hollyoaks

All semifinalists.

The cellist at the Royal Wedding was on BGT with his whole family
Sheku Kanneh Mason