I think you have to assess every socket individually according to conditions. I would not be happy that a 'blanket' email/memo would prevent every person in every circumstance using a socket by a door to supply equipment outside. I think you have to look at it like this: 'Is it possible that someone might use that socket to plug something in to use outside?'. You could send a memo out to every electrician saying that under no circumstances should he(or she?) touch a live part. It's just not possible to enforce and also not reasonable to expect it not to happen just because someones says that it must not happen.
SRCD's are not too expensive and could be fitted just in the locations where you consider there was a risk of someone using the socket to supply equipment outdoors. This is an area where there are no 'hard and fasts' and it is down to your interpretation of the reg's; if you have read, interpreted and understood, then you must make the decision based on your knowledge and assessment of the situation. I would say if in doubt, then make the recommendation that supplementary protection should be provided in accordance with 471-16-01.
According to the NICEIC publication 'Inspection, Testing and Certification', says that 'persons undertaking periodic inspection reporting need to have above-average knowledge and experience of electrical installation matters to enable them to safely and accurately assess the condition of an electrical installation...'. You either meet those criteria and are able to make that assessment; or you do not meet those criteria and should not be undertaking periodic inspection.
If you are in a position where you to meet those criteria, then in most cases the assessment you make must stand. It doesn't matter what the NICEIC or your boss says.
As for the client...I haven't met a client yet that says 'Please make your recommendations regardless of cost and with the utmost regard for health and safety'. Most of them say 'Does it really need to be done?'. This is the point at which your boss may say 'Well, not really because if you send out a memo....'. At which point you say 'Sorry, but yes. Neither you nor I can guarantee that that socket will not be used outdoors.'
Everyone will pull you in different directions according to their priority. Client-costs, Boss-continuity of work. You must be strong enough to stand by your decision. As for losing the work to other contractors, that will never change and people will always be prepared to cut corners to get more work.
This is the way I work and although I clash with people at times it can gain you a lot of professional respect.
; go for a standard split-load and ignore the 100mA RCD.
