Could you add a photo please Alan, the majority of Philadelphus are deciduous.

You had several replies to this when you asked it a few days ago so more replies would just be the same. . Philadelphus varieties that grow in the UK are not evergreen and the consensus was that your shrub is something else. Several alternatives were suggested for you to look up on google to see if any of them match yours. You were also asked then for a photo so one of us could probably identify it. We can't get any further until we hear the results of what we suggested before or see a photo or preferably two, one showing the whole bush and one a close shot of a spray of leaves.. If you need help adding a photo to your question just ask - heaps of folk here will be glad to help once we have more info.