I am over 70 , live alone and have had the letter. It told me I shouldn't leave the house, only fresh air through open windows, get someone else to put the bins out etc, etc. If I lived in a town or city I could understand, but I live on the outskirts of a small village, I can leave my small bungalow, in a cul-de-sac, without going down to the main road, I go onto the fields that are 25 yards from my door. I touch nothing, nor do I come within close distance of anybody if I go out for a walk. I think we have to use our common sense, the letter is standard and quite naturally, your own circumstances are not taken into consideration when they are issued.
Mind you at the moment a walk over the fields is out of the question, my hayfever has gone through the roof!!