Malachius bipustulatus

The red spot at the rear of each wing is the distinctive feature of this beetle that doesn't have a common name.
To be precise, the spot is on the elytron, which is a hard forewing, which protects the hindwing on beetles and a small number of bugs.
My reference book states these beetles are very common in "grassy places, close to woodland" - which is a perfect description of the reserve!
Adults feed on grass pollen and larvae hunt other insects under loose bark.