We came across two Ground Beetles, and they happen to be two of the commonest species in the UK. The top shot is the Strawberry Seed Beetle, Harpalus rufipes, a female. The elytra of this species look duller than the thorax, as they are covered with fine hairs, which you can see glowing in the photo below of the same individual, as they glistened with the flash light. They eat many vegetable matter, and appear to be partial to ripe strawberries.
The next species, larger (15-20 mm), is the Black Clock beetle, Pterostichus madidus, a very shiny, large headed species with impressive jaws and eyes. They are mainly predatory, and feed on ground invertebrates. This individual is a male, recognised by the enlarged tarsi of the forelegs.
There are many species of ground beetles (about 370) and many are hard to identify. These are some websites that might help you ID them:
Let me know if you know any others!