Could you please clarify something for me? I am slightly confused by the wording of Rule 16 in the context of your answer. Would the Examining Authority be able to make a site visit accompanied by only ONE interested party (i.e. to a private address/ land), as long as he informed other interested parties of his intentions? This appears to be what you are saying, but I am a little unsure as Rule 16 seems to only relate to accompanied visits for ALL interested parties.). I would appreciate if you could clarify this issue for me.

Rule 16(1) only applies to unaccompanied site visits. In other words, for a visit to be unaccompanied, and for Rule 16(1) to apply, no Interested party can be present.
Rule 16(2), in combination with rule 16(3) and (4), governs accompanied visits to any site to which the application relates - ie including private properties . If an Examining Authority chooses to make such an accompanied site visit it has to notify all Interested Parties of "the date, time and place at which it proposes to make the inspection".
Rule 16(4) enables the Examining Authority to proceed with an accompanied site visit if he/she so wishes, even if other Interested Parties are not present or represented on the chosen date and time.
It is at the Examining Authority's discretion whether or not to permit any other Interested Party to attend an accompanied site visit. However, for the Examining Authority to be able to visit any private property he/she needs the permission of the owner of that property/site.