Are you really sure you want to be prescriptive - just look at all the posts on here where 2m is not feasible so "what can I do"?

Depending on the pavement being directly on the edge is unlikely to be a good idea given the passing traffic particularly poorly loaded vehicles e.g. the car with a load protruding from the passenger window like the lance of a jousting knight or the cycle courriers trying to squeeze past stationary vehicles.

Or you state 12" and then end up in protracted debate because that is where the pedestrian railings or other street furniture are fixed preventing the use of the equipment.

Then there is the proverbial how wide is the pavement - in some back streets it may only be half a paving a slab others could be sweeping thoroughfares.

It is written as "suitable and sufficient" so that a judgement call can be made dependent upon the multitude of influencing factors which the surveyor should consider as they are setting up to take measurements.

Its because currently from time to time they are standing on the very edge, heavily engrossed in their task.

And you are correct there are a lot of cavalier delivery drivers etc in the area.

So in addition to getting the chainman/person to watch out for traffic and pedestrians would like to state they must be a mimum of xxx mm from the pavement edge, if they cannot achieve that distance would have to set up elsewhere.

Why not ask the surveyors to say what they think the rules should be? Don't accept the 'never had an accident yet gov', see if there are any close call anecdotes - you may be surprised. Definitely do not try to say a particular distance. Maybe talk about margins and different scenarios affecting level of risk.

In the ideal world all safety procedures would be developed from experienced users input, with only the legal or industry standard from safety practitioner. I wish I had learnt this sooner in my career than I did, and implemented it better than I may have.

I take it your employer does not want to pay for (or may not be permitted) a roadway suspension whilst the surveyor works.

How's about an assistant similar to a mobile camera operator - the assistant constantly watching behind (or to the flow of traffic) for approaching hazards whilst the task is completed?

Appreciate this takes the task from two to three people but in a busy metropolis where your RA is meant to reflect what can be considered suitable and sufficient controls rather than a piece of paper to try and vindicate the employer from any liability in the event of...