I am surprised that she is allowed to walk 7 dogs at a time even as a professional dog walker, I thought the upper limit was six only at any given time in a public space.
In the area in Hampshire where I live, a new by-law was introduced in 2017 under the Public Spaces Protection Order allowing people to walk no more than 4 dogs at a time in a public space. (Previously 6) Otherwise a fine of £100 will be issued. I am pleased they have introduced this rule as seeing a few people trying to manage 6 dogs, while cleaning up their messes and still keeping an eye on the others is quite a feat to attempt and not always successful. We are right on the coast, a really busy area, ideal for dog walking, unfortunately the few spoil it for the many, either not cleaning up after them or allowing them to be unruly and causing problems. Hence why we now have this new by-law and it seems to be working very well.
A dog warden also is a deterrent to enforcing these regulations