The tree was sponsored by me for the Cloud Appreciation Society (of which I am a member) in 2016 when these pictures were taken. The notice board was offered by the then Director of Hillier Gardens, Wolfgang Bopp.
I've never heard the common name "Lollipop Tree", but it appropriate. It's a very good cultivar, and widely planted in France. I often drive by a large horse farm which has a long aisle of these at the entrance, very distinctive even in winter even though they are only perhaps 25 years old. I remember when they went in. Thanks for posting! -E