
I had the same problem and still do sometimes.
I set up a thing in our local parish mag called Poo Watch.
It went on to explain about people being more aware of people who blatently didn't pick the poos up and should start to report people who we all knew were the persistant offenders. Last sentence said "Nobody can hide we are all watching you and we will not hesitate to report you ! '
Combined with some laminated flyers which the PCSO provided after I walked them round the worst areas to make them more ware if they did their rounds the poo did decline although didn't stop completely.
I ahve also caught a few people in the act outside my house and have marched out and thrust a bag into their hands and stood there saying unless they oicked it up I would report them . The shame on their faces was priceless !! :-D