How to find a good Krav Maga School

People buy into Krav Maga because of it's reputation, it's history and it's evoloution. But in an unregulated industry some Instructors can and do make a range of misleading claims about themselves or MartialArts they describe as 'Krav Maga'. Fake Krav Maga is like any other knock off. It looks vaguely simmilar on the outside - well at first glance at least...