Ah!! Now I think it may well be Leycesteria formosa . If so, the stems will be hollow, and the flowers will look like this It is pretty when it first flowers, but then the birds will eat it and not only spread seeds all over the garden, but poo bright red all over your washing, your car, everything else, and look like the scene of a murder. PITA
Another picture of the shrub in question, top right. I'm now thinking Azalea. The shoot in the original pic is attached but doesn't seem to resemble the mother plant, perhaps it should be removed.
Excuse the state of the bed. Although it sits outside my daughter's home it's managed by an estate landscaper. Doesn't say much for the landscapers abilities does it? Daughter wants to take over management of the bed and replant most of it.