I'd fully support a limit to the numbers of dogs walked by commercial dog walkers and licencing of said walkers by the council and as AngelGabriel said, identifying bibs/tabards so as to place accountability when and where due.
I often speak to commercial dog walkers in various park across the borough and most if not all of them have the same view.
Fortunately I've never witnessed a frenzied attack by a pack of marauding hounds on either another dog or a person and frankly suspect elements of hysteria and exageration. I have however witnessed the dogwalkers picking up dog mess left by dog owners as a norm, in part to limit accusations levelled at themselves and also to maintain a relatively pleasant area in which to carry out their duties.
I also have no faith in the local council carrying out an unbiased consultation and effectively implementing any valid controls as a result. I suspect the commencement of the consultation being delayed from July till October will also prove in their interest as the other concerns people have with parks and open spaces such as arson, vandalism and other antisocial behaviour issues will have somewhat abated with the start of the new school term.
Dog walkers provide security in parks by virtue of being there. Many people would avoid areas such as One Tree Hill because of it's isolation if the dog walkers weren't there.
Push for effective and rational controls that will be enforcable rather than illconceived reactionary ones.

Brian, I don't understand your ethical logic on world food shortages having any more bearing on feeding pets than you spending your hard earned on anything other than essentials. Could it be that the monthly payment you make to your internet provider would be much better placed helping to reduce the aforementioned shortages?