Presumably the same as an unchartered person with an MEng. A person with a BEng can still become chartered though, the only advantage of having a MEng is that you are exempt from certain conditions for your chartership, and also that it makes you a more competitive applicant for jobs. I wouldn't think companies have a separate salary for those who did a BEng and those who did an MEng.
I feel you're misunderstanding chartership a little however. I was once told by a very senior engineer that chartered engineers don't earn more because they're chartered, they earn more because they're generally more experienced. So it's not like you get a pay rise once you're chartered, but that most senior engineers will be chartered, and those are the ones earning more.