RoSPA are much tougher. I have held the Gold certificate for RoSPA for 23 years and you retest every 3 years if you get Gold or Silver (Grade I or II) and every year for Bronze. They are also much stricter as well. IAM is a one off, but it is a good place to start (or at least was 23 years ago). I have been an observer/tutor/whatever they are calling us this week for both, note the past tense. I quit 4 years ago on the teaching it voluntarily side of things.