[MargaretR]

A couple of years ago I campaigned to get dog bins installed near my home, which overlooks playing fields used by many dogs per day.
They were installed after about 18 months of pestering.
I had several visits from the dog warden and environmental health officers, who are trying to lessen the problem, but they are hidebound by needing 'proof'.
I did make a one day minute by minute record of the number of dogs on the field and the total was over 50.
I didn't actually count 'piles' but that may be what is needed in the street areas, in order to convince the council to increase the number of bins.

There will be some objectors to bins placed on lamposts near their front doors.
Hence there is no easy solution to this problem.
The provision of bins has reduced dog fouling near me.
Even when I am not looking out of my window I hear the bin being used as the lid slams down after a 'deposit'.

I supplied the car registration numbers of regular daily offenders, and monitored the usual time of day when the offenders visited.
I know that the environmental health people did use that info to give warnings.
In a street situation you would not be able to use that as an means of ID.

The only solution is to ban dog ownership (other than guide dogs) in built up areas.

This situation may partly resolve during this depression, as more people abandon their dogs for financial reasons.