Or alternatively you do what I did yesterday, and talk to a manager. It probably isn't in their best interests to tell lies to regular customers, and in any case he did specifically quote from their trade magazine, "The Grocer".
I already happened to know that their logistical problems are down in part to Brexit. Whilst they own/lease their own trucks, a mixture of class 1 and class 2 vehicles, they used to employ a fair few agency staff as well as using cabbotage to cover their deliveries. Since Brexit there has been a marked decline in the amount of cabbotage using EU drivers in the UK and a lot of Eastern European drivers have simply left and won't return. So there is now a shortage of drivers.
The food manufacturers, many of whom had a goodly percentage of Eastern European staff on their production lines have also lost staff - and have consequently had to cut some of the more labour intensive products out of their ranges.
I live in an area where there is still quite a bit of agriculture, but where local abattoirs have been struggling not only to get slaughtermen and butchers, but where they sometimes have had to curtail production because there are no inspection vets available to oversee livestock health (a legal requirement). Grom my locsl butcher who I have known for more than 20 years (and not least because we used to drink in the same pub)
I've noticed that a lot of the fresh produce we buy has a shorter shelf life than was previously the case - partly logistics, but also partly lack of picking staff (East Europeans again)
And on and on this goes. But Brexit supporters seem to have "Nelsonian 20/20 vision" and fail to see anything going wrong. And, like many other things in life, if you refuse to admit that there is something going wrong (like, say, an alcoholic), then you will hardly be willing to take steps to fix it. Note, I am saying fix it, not rejoin, not remake the world, but actually just FIX IT!