Hope someone can help!?

Over the past two years, the Spotted Laurel in a large garden I've been working in have suffered almost total devastation with mass dying of the shrubs. I have been aware that the property next door is suffering from the same problem. The plants have started wilting first, then leaves blackening and dying, then subsequently the whole plant dies right down to the roots.
I have posted/uploaded some photos, ranging from a healthy looking tip to the inside of the dead trunk/stems showing the state left on the inside. Also a couple of the dying and dead foliage/stems.
There are other 'laurels'(Bay,Portuguese and English) as well as various regular shrubs and trees of other species which are totally unaffected.
Up to now, apart from asking anyone(gardeners/garden centre staff) whom I think might know the problem, I have cut out and burned all affected plants as they occur and now have very little left with no signs of it abaiting.

Thank you for any morcel of advice however small. The phots will either be linked on this post or on the Garden Photographs section under 'Dying Aucuba!!'

Terry