According to ru.wiki, the V-2 quality was very poor.
20% of the assembled rockets were sorted out, and every second of the launched ones exploded on launch.
I.e. 20% - sorted out (i.e paid but not used), 40% exploded in Britain, 40% exploded in Germany.
Conclusions;
1. Britain and Germany have been bombed with equal amount of V-2.
2. Germany was harmed by V-2 program more than Britain was.
3. While in Britain V-2 were hitting random, useless in military sense positions, in Germany most of them have hit rocket launchpads.
3.5. V-2 was the most effective counterforce anti-launchpad missile in history. Just reversed.