I'm inclined to believe you. While I definitely did not see a Turner Scott despite looking for it, and I definitely did see Fettle, I did feel after making this note that my GPS position relative to things on the map seemed off compared to my position in real life - so I could have been led to look in the wrong place.
I have also made errors like this before on StreetComplete, which leads me to ask - should I continue to make edits like these where I believe new shops have popped up and risk making poor quality changes, or am I doing more damage than I am helping and I should leave it alone? I suppose with practice I'd eventually be better but until then I could end up causing problems - so I won't be offended if the answer is that I should avoid adding and removing shops on StreetComplete!