Aiden, it all depends on your personal circumstances and aspirations? I would say that the majority who have gained your qualification would wish to get CMIOSH, due to the market forces. Many employers require a professional membership/accreditation. I believe an environmental qualification would be advantageous. If you are in employment the choice would be down to your aspirations. Good Luck.

Morning, I agree with the posts of Steve & Freelance, I would advise you to start your IPD as soon as possible after gaining Grad IOSH status, maintaining your CPD is mandatory so you have no option. You should be able to combine courses with IPD & CPD. From the date you receive your GradIOSH you have a minimum of 2 years before you can become chartered, in which time you will need to complete your CPD & start/complete your IPD This period is required to demonstrate your experience and possibly gain more. I was able to combine my work, new courses/skills and my IPD without taking up too much spare home time. Certainly nowhere near as much as doing the diploma. I did however use my lunch hours to write up my IPD but as IPD is about demonstrating how you are developing your competence it is probably going to be about the work your are doing anyway. One point to remember is that after submitting your IPD portfolio it probably takes about 6 months to have it reviewed, pass your peer review interview and go through the approval process but I believe that you can send in your IPD portfolio at about the 18 month stage. IOSH IPD & CPD on the web will help you if you have any problems or ring direct and you will be assisted. Take Care & Good Luck