That’s interesting, though the camera is more sensitive than the eye. I took a few shots myself and M is clearly visible.
Here’s a (possibly dodgy) hypothesis:
1. The current ‘lockdown’ has reduced the volume of pollutants in the atmosphere.
2. This has increased the effects of light pollution.
3. This will be especially significant in urban areas (such as here, between Manchester and Liverpool).
4. Ergo a) stars around the mag of Megrez will be pushed closer to the limits of naked-eye visibility. The effect on Megrez itself is especially noticeable because of its prominent location. b) this effect will be more visible from urban (heavily light polluted) sites than rural ones.
In principle, these implications appear to be amenable to test fairly easily.
However, this reasoning seems to imply (counter-intuitively) that atmospheric pollution reduces light pollution which improves seeing!