According to the Letters to Venetia Stanley book, there are 2 more letters that day, but their contents are not currently in the digital archive.

No specific UK news reported in sources.

"St. Loe Strachey came to talk to me about a forecast of our new coalition cabinet... H. came into the room and said he was sorry Redmond would not come in..."
"On Friday [21 May] we went down to Walton Heath. I went home to tea first, as it was Muriel's birthday. ... On Thursday Mr. Murray asked us to dine..."

"Mamma and I lunched at Downing Street, where a tremendous atmosphere of tension and distress prevails. Mr Asquith... looked tired, worried, busy, or preoccupied..."
Searching 1912–1916 Archive