New toy

Great excitement.  My new mid-range zoom lens has arrived so used our evening walk to give it a wee whirl.  Some nice shots of the growing cynets on the canal ensued.   Then I headed for the garden to try some close-ups and decided to blip this white flower.   At some point I would have saved a label of what it is but that is long lost.   It flowers pretty much all summer and the bees love it but I need to try and find out what it is so I can work out how hard I can prune it in the autumn as it's getting quite straggly.