If your supermarket has introduced queuing, then the chances are that the shelves will be better stocked. Also, don't go at the usual peak shopping times.
I went to my nearest Sainsbury's at about 7pm the other evening. I joined a queue of three people, and when we were let in (after about a minute's wait), there was much more stock on the shelves. In fact, it was a nicer shopping experience than the pre-crisis days. Very quiet and relaxing. I bought everything I needed/wanted, apart from grated mozzarella, but that was just me being forgetful.
Mind you, the old guy in front of me at the till bought about 20 bottles of spirits and nothing else, which is a form of panic-buying I could approve of. The customers were limited to three of each item, so he had three bottles of gin, three bottles of whisky, three bottles of vodka etc. etc. No mixers.