Number of PRAs required - None, though at least one is definitely preferred and recommended. Please remember that the PRAs are volunteers giving up their time to help so don't look for a second PRA unless you feel it is necessary (e.g. if the first PRA has insufficient experience in your particular field of work).
Application support or endorsement - minimum number of supporters is actually one, but you must meet the requirements for your particular situation. The IET guidance on supporters is as follows:
• Mandatory: a supporter who knows or has known you professionally, working at a senior level to you and with direct knowledge of your role and responsibilities, such as your current line manager, employer, Academic Supervisor, or Training Scheme Coordinator. You must detail your relationship with your mandatory supporter
• Preferred: as well as the mandatory requirement, it is preferable, but not mandatory, for a candidate to have an additional supporter, who is an Engineering Council or international equivalent registered engineer. This person would be a Member, or Fellow, of either the IET or another Professional Engineering Institute (PEI).
• A second and third supporter is optional and may be necessary, for example, if you work on contracts, as an additional signature to enable adequately verified periods for your employment.
If you have not read the application guidance, I would recommend downloading it and checking you have everything included. Your PRA will have checked as far as he is able, but even he can't say you have missed something that you know about but he doesn't. A second pair of eyes is always useful anyway. If you can't find the guidance notes then your PRA should be able to help.
