(Echoing PharmaT, but I'd already written most of this when she posted)
Sorry Ray but you are totally wrong as the guidance specifically includes -
"for any medical reason, to donate blood, avoid injury or illness, escape risk of harm, provide care or help a vulnerable person"
The reason for leaving London was covered by the above.
In DC's opinion (and yours, it appears). But which of these
required him and his family to make that journey? What was there in Durham that couldn't be provided in London? And why is it thought acceptable for him to travel to a distant family property (lucky him - his family happened to have one spare) when other people were explicitly told to stay put?
And Guy - do you consider it to have been within the letter and/or spirit of the guidelines for DC to have returned to work, even though his wife was thought to have COVID-19 symptoms and he was worried that he might also have the virus?
We're not all useful idiots.