I expected Cummings to be more abrasive today, not sure whether he is genuinely concerned at how this is going down or is acting up for sympathy. I would guess the former given the timeline of Downing Street's response.
The Barnard Castle excursion is indefensible, not that I expect that to stop people.
Firstly, the DVLA pretty clearly does not allow you to drive to test your ability to drive
https://www.gov.uk/driving-eyesight-rulesbut more importantly, if we have to excuse his behaviour because it was all within good judgement, I'm concerned about the judgment of keeping your wife and child in the car for a test of your ability to drive.
I imagine the defence will be that he had them in the car so as to not waste time travelling back to his parents' house and then back to London which might be legitimate if going to the Castle was directly on the way but it appears to have been something of a detour.
The defence of driving to Durham was slightly more convincing but if he can justify a symptomatic family driving 260 miles why couldn't the asymptomatic people in Durham who had volunteered themselves for childcare drive down to London? I believe he mentioned a 20 year old who you could presume can drive - maybe not but he should at least answer the question.
Pretty horrific excuses all round and a shame that the journalists were not more forensic.