When I was looking after agricultural inspectors the issue of dogs often came up. The policy we agreed upon was basically the following:

1. Dogs are a hazard and we as an employer will not allow our staff to be exposed to a risk from dogs. Any sort of dog bite was unacceptable.
2. Although staff had certain duties to carry out, they we not expected to put themselves at risk to get the job done.
3. When they entered or approached  a property  they were told that if there were dogs running free they had to contact the occupier(by phone) get them to get the dogs under control ie chained up or locked up.
4. We had leverage that if we were prevented from entering a property we could take some action, basically not inspecting the property which would have consequences for the occupier.

Edited by user 07 January 2020 16:19:31(UTC)  | Reason: spelings

Yes it is down to risk assessment. We have similar arrangements to A Kurdizel above. My colleagues are all instructed not to enter or to leave a premises if there are dogs present and they do not feel comfortable.  Some of them have powers of entry so if they are prevented from entering by a dog the occupier could be charged with obstruction. For other’s they want the person there and so if they don’t keep their dog under control they have no chance of getting what they want.

Before I started in my current role “post pegs” were also introduced for where doorstep mail deliveries were undertaken. I believe the post office use similar there are images on the internet. Basically keeps you finger away from the letter box if there is a snappy box behind.

My father in law used to be a post man many years ago and had a technique which was where there was a snappy dog behind the letterbox he would put the latter partly through then draw it back. Having done this a few times the dog would have basically shredded the letter. Said he soon found people kept their dogs under control! Not sure he would get away with that today!

Why would dogs be roaming around a commercial site? Are they guard dogs? If so they are subject to the requirements of the Guard Dogs Act 1975 see https://allaboutuklaw.co.uk/guard-dogs/ for more information. If your guys ( and gals) are engineers coming on site to fix things then  you can simply make it clear to customers if that are dogs about which are not under control, you don’t turn up to fix things. That’s your leverage.

Agree with the comments above about guard dog’s whole different ball game than the average family snappy pet – and they can be bad enough I know.

Have used an electronic gadget which I think will be similar to those Zyggy mentioned. Mine was a Dazzer – supplied through the local authority dog warden. I could just faintly detect when I used it a very high pitch wine (was much younger then hearing probably not as good now!) and it was great, but I only used it when I felt threatened – i.e a dog was coming running at me barking etc. However we were warned when they were supplied that a trained dog – such as a police dog or some guard dogs would not respond as their training would override their natural response.