This language actually is the language that one uses in statutes to give maximum protection to tribunal members. In a sense, it's redundant, because it says that each member holds office “during good behaviour”, which means they can be removed only if they do something contrary, which would have to be established at a fair hearing and all of that. They could be removed only if they were to do something contrary to good behaviour, which would be that they were in a conflict-of-interest situation, or they did something wrong, or they did something unethical, something like that. It's a high standard, and it would have to be proved in any hearing. Then, the remainder of the sentence, “and may be removed for cause”, is actually the same thing. There has to be real cause.
Actually, it's saying it twice to be absolutely 100% clear: the people are appointed on “good behaviour”, not at pleasure, for instance, which would allow them to be removed for any reason at all. It's on “good behaviour” and only “removed for cause”.