John Gascoyne Lake (1903-1975) Studied painting at Eastbourne School of Art 1918-25 and at the Royal College of Art 1925-29. He was later the curator of the Towner Art Gallery in Eastbourne 1947-58 after which he retired/emigrated to Spain. Exhibited with the New English Art Club (NEAC) and with the London Group (LG). There was a memorial show in 1975.
There are a couple of his watercolours for sale on Ebay at the moment, I just noticed. They've confusingly spelt his middle name as "Gascoigne", though, rather than how he apparently spelt it and re how he's listed otherwise. They're 380 each. Whether they'll sell at that is another question.