I generally use Raymond Murphy's excellent grammar book English Grammar in Use with Answers: A Self-Study Reference and Practice Book for Intermediate Students of English but was looking for something to supplement it. I bought this book because it appealed to me that it was aimed at a lower level (A2-B1) and some of the points it covers are excellent for this. However the biggest criticism I have is that some of the units are far from clear. 'Rules' are given but then in the exercises exceptions to the rule pop up with no corresponding explanation which causes real confusion amongst students.
As I say, I have found it useful for some teaching points, but it needs to be handled with care. There are other better grammar books available.
A very worthwhile book for anyone with the background to teach business English. The book is full of practical exercises and systematically takes you thru' the right/sensible sequence of grammatical tenses in a business context. Definitely recommend this book.