I don't want to start a huge diversion on this topic but this does seem to be an area where different sparks have different interpretations both as to what's in scope, and what constitutes continuous supervision by skilled or instructed people. If you look back at previous threads it's been discussed before on this forum and the iet forum.
I have some sympathy for the argument that the more structures move, the more relevant section 717 is. For example an outside broadcast unit (in a past life I drove one and was the resident engineer) could move every day and be connected to a different supply daily. That is a good example of something being under continuous supervision too. Which is handy as banging an earth rod in at every venue for the antiques roadshow isn't really practical!
Even if this section was in scope, it's been pointed out there is likely to be someone skilled supervising things on a construction site. So PME would be allowed.