"...by the time the Police become involved someone would have at the very least 'Obstructed' a Council Officer in the course of his/her duty."
They may very well have done, Balders. But since such action does not constitute a criminal offence there's nothing to be done about it. Litter/dog fouling wardens have no powers as such. They cannot detain anybody, they cannot search anybody. They can ask somebody for their name and address but that person may simply walk off.
Quite how Blaby District Council (or whoever came up with this scatter-brained idea) hopes to see its enforcement is a mystery. The only time it can be enforced is if there happens to be a police officer around or a PCSO (who has the power to detain a person for 30 minutes until police arrive). I actually think it is very good idea, but that its enforcement (among those who allow their dogs to foul) is virtually impossible.