Katherine was in London and was thrilled her dear young brother - "Chummie" as he was called in the family - was in the same country. On leave Beauchamp stayed with his sister at St John's Wood and the pair shared memories of growing up in New Zealand.
Letters held by the National Library in Wellington reveal the affection the siblings held for each other and the hopes Beauchamp held for his future back home: "I shall occasionally take a trip to England - anyhow shall retire from business by the time I am thirty eight or forty."
The papers also show something of the company that Katherine, by this time a published author, was keeping. The address on a letter from Leslie to his sister dated March 11, 1915 is crossed out, and the envelope redirected to "D.H. Lawrence, Greatham, Pulborough, Sussex", a village 75km southeast of London. Mansfield and her partner, John Middleton Murry, were friends with author Lawrence and his wife Frieda.
In one letter Beauchamp sent to Mansfield, he writes of his distress at learning that that she was unwell. The 21-year-old said he felt "intolerable" grief because he was helpless to be of any aid.
Complaining that the colonel in charge of his unit was unwilling to grant leave, an agitated Beauchamp continued: " My darling my heart bleeds for you. Would to God I could alleviate your suffering but you can see how helpless I am."
Beauchamp was billeted in Bournemouth, attached to the 8th Battalion, South Lancashire Regiment. He told Mansfield to be specific with the unit when she wrote, because other regiments included the "East Lancs, Lancs Fusiliers and the Royal North Lancs" and the odds were 10 to one against receiving eagerly awaited letters if they were misaddressed.
"Our Regt is 8th South Lancs," he stressed, underlining the '8th'.
Expecting to head for the front within a few weeks after infantry training, Beauchamp proudly told his sister that he had achieved "great popularity" with fellow officers, who for the most part were "charming young fellows".
Perhaps aware that Mansfield struggled financially, Beauchamp urged her to let him know "if there is anything you were wanting in the way of money or anything".
He signed the letter "Ever your devoted Chummie."
When autumn came, Beauchamp left for the front. He let Mansfield know by telegram on September 25, 1915:
"Off at last the goodbye would have been too awful
au revoir, Leslie."
On October 5, Beauchamp wrote from "Somewhere in Flanders": "Am frightfully fit and full of beans!" The trenches were "beastly wet" but he was unscathed, he reassured Mansfield.
Two days after that letter Beauchamp died, instructing soldiers in the use of grenades. One exploded as he held it in his hands and he bled to death.
His commanding officer wrote to Mansfield to say her brother survived for 10 minutes after the blast but his "actual suffering was slight".
He was buried the same day.
Leslie's death floored Mansfield, and she fled, grief-stricken, to the South of France. By way of tribute she wrote a poem for her brother called
To L.H.B. (1894 - 1915)
It opens:
"Last night for the first time since you were dead
I walked with you, my brother, in a dream."
