https://www.college.police.uk/What-we-do/COVID-19/Documents/What-constitutes-a-reasonable-excuse.pdf?fbclid=IwAR2U9-JJ1CfdZjIZX1eifDH1cJtNcqYvM9J5VoRsY6N3lxnPxATXHsLrVR0
Some very good guidance here on how the police are interpreting the guidance.
I would challenge this in the "Not likely to be reasonable" column: "A short walk to a park when the person remains seated for a much longer period" as it may be discriminatory against people with physical or mental disabilities. I saw such a person sitting on a park bench last week with his companion or carer. I have been in that situation in the past.
I'm not happy about "buying paint & brushes to redecorate a kitchen" being in that column either.
I think that the Government et al are trying to avoid being too prescriptive in their rules and regulations, precisely because they do not want to get into a blanket shut down such as has been seen in Italy and Spain. For example, it would be entirely reasonable for a person with physical disabilities to spend some time sitting on a bench midway through a walk. However, it would not be reasonable for me (or any other fit and healthy person) to sit there for longer than a couple of minutes (the sole purpose of leaving the house being to have got some exercise rather than sit and enjoy the view).
Now obviously, there are additional difficulties with unseen/invisible health issues, or other issues such as at risk of DV, and in those situations I would hope that should a passing police officer question why that person is sitting for a while, a very brief discussion would elucidate the reasons and a compromise would be reached.
It is the same with leaving the house to get food - I am in the fortunate position of having the money and fridge space to be able to do a shop that lasts 10 days or so. It would be irresponsible of me to go back to the shop every other day when I have no need to do so. However, someone who only has a small fridge/limited budget will need to shop more frequently and should be allowed to do so without fear of being 'called out'.
Frankly (and this is comment is not aimed at anybody, but rather my general thoughts) people should be more worried about taking responsibility for their own behaviours and physical distancing, and less worried about judging others.