I bought a panda harness for DS and found it wasn't that helpful because he goes on strike (sits down, lies down) and so I'd end up having to carry him anyway. And I can't carry him very far, especially if he's struggling. I'm 5'1" and he's now 16kg. Shopping continues to be a nightmare. I've recently begun doing online grocery shopping to avoid the worst of it. An option that only became available to me this year. Yesterday I took DS to DFO so that we could buy him a little guitar and a book. Never made it to the shop as he kept lying on the ground. I managed to con him to let me carry him a little way and I took my chance and got him out of there. He turns into an ironing board and screams if I try to put him into the stroller or into the seat on the trolley if he doesn't want to go in it. When he goes in without fuss and stays there, he is lavished with praise.
I will try the harness again though because he has given me two frights recently, walking away from the car without waiting for me and starting off across a carpark without waiting for me. My thinking is that even if your child is perfectly compliant and well trained to walk with you it just takes ONE momentary lapse and they're gone forever. I couldn't imagine my life without him in it. I am hoping the harness will work this time. If I had someone to go shopping with me, maybe it wouldn't be that awful. But single parent I am and I work full time. That's my reality. Of course the other option is to do all my shopping online...