Hi Mark , it's certainly a small world ! yes I knew John Leslie a wonderful accordionist and teacher and of course a real character . Never visited his shop in Kilburn London , but spoke to him many times at various accordion festivals .
A very good friend of mine Andy Anderson (another wonderful accordionist) was John Leslies right hand man in the shop and at accordion festivals!! those two guys where like accordion brothers !!! and John Leslie actually brought out the best in Andy's accordion playing and john Leslie loved Andy's musette playing and his help and advice gave Andy the confidence and self esteem he had lacked most of his musical life (this is what Andy told me !!!)Sadly Andy passed away a few years ago and I'm sorry to report that John Leslie passed away about a year ago .
As I'm sure you know John had 5 children at least 2 of them are terrific accordionists ...so john's incrediable talent lives on as does his accordion shop .

Mark is there any chance you could just post the link to the site you mentioned , I'll then try to open it..
As the subject is of great interest to me....best regards