Plenty of these at the Dams - Great Willowherb or "Codlins and Cream" Epilobium hirsutum
This is Water Mint Mentha aquatica. No prizes for guessing where they were!
Here are 4 hoverflies of the species Episyrphus balteatus on a Dandelion flower. These appear later in the year than most hoverflies and are now everywhere. They are gardeners' friends because they are fond of aphids.
Finally here is a Hedge Woundwort Stachys sylvatica