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.

German submarine U-22 accidentally torpedoed and sank its own sister ship U-7 in the North Sea.
"C. is not very well today. He has been working very hard, but personally I think he is suffering from too much ‘family’. He was very upset on Monday [18 January] because not one of them had remembered that it was his birthday on Sunday... C. is to go over there [Paris] in February to meet M. Ribot & the Russian financiers."

"Dined with Donald. Sir Thomas Lipton guest of the evening. He told me that he took the Empress Eugénie to Marseilles... Also that when King Edward went to Kiel, the German Emperor sent to inquire “whether he had brought his grocer with him”..."

"Shortly after my arrival this morning I was sent for by the P.M. At 10 Downing Street I found Sir Edward Grey and Lloyd George. The Prime Minister said that as Lord Kitchener was away he had sent for me."
Searching 1912–1916 Archive