Some of the info was quoted as the sea ceptor, some may have referred to the CAMM air launched version which would have a longer range. the info was from testing which had occurred, sometime around 2014 or 2015 so was definitely not the ER. If the range of the sea ceptor is 25 km at sea level then this could easily give a range of 50 km at high altitude.
What we do know is that MBDE and the RNZN claim for Sea Ceptor an effective defensive envelope of around 1300km² which using basic math would accord to a radius of roughly 22km. That is not to say that the range is longer but where the kill zone is. Which suggests that about where it might be a great idea for the missile to hit what its meant to hit.