Carol you've done nothing wrong here, and you don't owe anyone an explanation.
I sometimes see a dog owner (not all dog owners), letting their dog poop without cleaning it up. It's just a fact of life that some people are like this. However, I would in no way seek to harass anyone in this way, because people (including lone WOMEN, driver) could very easily get the wrong impression. Unless of course, the accusation regarding the dog pooping wasn't the real reason this person was following you. See what I'm saying, folks?
How long was this person following you, Carol? Always carry a phone and look for potential witnesses. Carry a personal alarm. Tell the person to go away. If they continue tell them you have their registration and will call the police. Then try and find a populated area. If they continue scream for help and let the personal alarm go off.
Dog pooping is one thing. Harassing lone women is another matter entirely. If this person wants to continue their issues then they should contact the council, not follow people around.
Are you being serious? Someone parks in two spaces at a Tesco car park and you choose to take the time to take a picture and upload it on to a website? Maybe spend less time going to Tesco.
No wonder the car has a Repainted boot