In reply to MarkJH:
> The regulations don't (for example) apply to mountain guides, so I'm not entirely sure what the cutoff is.
The exemption for mountain guides, climbing and caving instructors etc that was in the 2005 regulations was only temporary and was removed by an amendment that was introduced seperately in 2007. It is a little bit academic though, in the sense that the amendment also conceded that existing good practice was good enough as an "equivalent level of safety" to the more proscriptive stuff that applies to other work.
The "explanatory memorandum" attached to the amended regulations covers a bit of the background to all that, if you can be arsed have a look at chapter 7 here:
http://www.legislation.gov.uk/uksi/2007/114/memorandum/contents
(There's also a ton of discussion about it at the time archived on here.)
In the run up to 2005 it looked like the introduction of the regulations was going to be an absolute disaster for mountain guides etc. There was some fairly frantic lobbying involved in getting that temporary exemption in place, and it was all a bit of a result really when the regulations as they were eventually applied turned out to be so sensible. (All of which is irrelevant to route-setting on an artificial wall, which was always "Work at Height" in the more conventional industrial sense, as above.)
Post edited at 23:01