I found this plant/shrub in my wildflower border last year. It grew rather large (as you can see from the first photo) so I moved it to the border next to the back fence. My attempts to identify it have failed, but it now has some rather distinctive flowers.
Coincidentally my father who lives about 250 miles away also has the same unknown plant in his garden (also flowering for the first time this year).
Does anyone have any idea what it is please?