Colonel Kelsall was a neighbour of Arthur Ransome; his house Barkworth was near Low Ludderburn in Windermere. AR went fishing with Kelsall; in the middle of December at Appelby they had to break the ice at the edge of the river first (AAR p328).
Their sons Dick (Richard) and Desmond (Des) were ten and six when AR started Swallows and Amazons. After Desmond read it, AR asked him what he thought should happen next. He said that John was too good; he should be over-confident and do something really stupid like wrecking Swallow. AR hooted with laughter, and said that was exactly what he had planned (CFT p50).
The boys Dick and Desmond went fishing with the Ransomes, and ran errands for them. Low Ludderburn did not have a telephone, so AR and Colonel Kelsall developed a system of signalling from Low Ludderburn to the barn at Barkworth, similar to that in Winter Holiday. The boys offered the youthful company that AR needed to write well. They posed with Peggy and Joan Hudson for the "Hollywoods", photos that AR used for his drawings e,g. of doing sums and capstan-turning for Peter Duck (CFT p50 & photos 28,29,30).
Dick Kelsall went regularly to see AR in Cheadle Royal Hospital in 1965. He was unable to speak and near death after a series of strokes, but was excited by reminiscences of the pleasure given by his stories (TLE p365)