John, As you would look to "Dirr", I have had a look through "Hilliers" and find the following: "Prunus laurocerasus 'Castlewellan' syn 'Marbled White' :A slow growing dense bush eventually of large size. Leaves green and grey-green, marbled throughout with white. Originally grown as 'Variegata'. From c 1811. Award of Merit 1986"
Castlewellan is a garden in Northern Ireland. My own comment: while it might catch the eye, I could not abide it in my own garden.
Paddy