The early peak records are also often on holidays or weekends, as total demand is lower and coal/gas gets shut down first as it has a higher marginal cost.
Still good to see progress, but you're going to see records broken regularly for years to come as the instant, hourly, daily, weekly, monthly, yearly records get broken again and again.
https://www.theguardian.com/environment/2017/may/26/solar-po...
Now, the caveat is that was at "solar peak" one afternoon in May.
As I type this, on a grey afternoon, solar is providing 6% of the UK's electricity. See http://www.gridwatch.templar.co.uk/