I am Derek Leckie, a grandson of Dr Walter Leckie.
I first heard of Robert Leckie via Eduardo Lobo who is a great grandson from Doctor Walter's first marriage.
My grandfather had four children from his first marriage; Olivia, Walter, Vyola and Sylvia. No Roberts as I understand amongst their offspring. His second marriage to my grandmother produced Vivian, Charles, my father Walter Francis, Alex and the two girls, Corina and Yolanda.
I know all my cousins apart from any that my uncle Alex may have had. We lost touch with him after he went to Australia in the twenties and then later on to South Africa. Perhaps Robert is a son of his.
I guess your interest is from the guitar/Tarrega angle rather than Leckie family history! One clue that may be helpful - in an email from Eduardo he mentions Brendan McCormack (BJWIRRAL@aol.com) who was the director of a guitar festival and borrowed the Leckie/Tarrega collection of guitar music from a Robert Leckie of Richmond, London. Perhaps he can help you.
For your interest my father told me that his Father left a fine collection of guitars to one of the museums in Barcelona,and when I was studying singing in Germany he gave me a lute of my grandfather's. Unfortunately I left it there, but I am happy to send you a picture of the maker Raffaele Calace, which is all I still have.
I think my son of seventeen has inherited the guitar passion gene. Since we bought him a guitar 3 Christmases ago, the instrument has rarely been out of his hands. And having just completed school in France, he is starting a year at the Institute of Modern Music in Brighton studying the modern guitar, after which he has plans to spend a year in Spain with the classical.
I'd be really interested to hear about your projects and am happy to do anything i can to help.