Dominic Cummings said he and his family went for a walk in woods next to the cottage where they were staying and were seen by some people.
He said it was in "the second week" of their visit - one can assume it was sometime between 4 and 11 April.
Was this within the guidelines?

On 7 April, Public Health England’s website said people could go outside for daily exercise even if they had coronavirus symptoms:

“If possible, you should not go out even to buy food or other essentials, other than exercise, and in that case at a safe distance from others."

However, on 8 April, the advice changed and people with coronavirus symptoms (or living with someone displaying them) were limited to taking exercise in their homes and gardens: “If you feel well enough you can take part in light exercise within your home or garden,” it said.

There was another change on 9 April, in which gardens were removed from the exercise advice: “any exercise should be taken within your home”, it said.