GGB Seven things, in writing: the fee basis and its scope; whether they earn a margin on suppliers; who holds the licensed roles; what the deliverable of the first phase actually is; what proof they can show and under what consent; what is owed at a stop; and who you will actually deal with. Compare the written answers, not the meetings.
From How to Compare Restaurant Consultants in Dubai: Seven Questions to Put to Every Firm in Writing — the full reading, with the method behind this answer.