Unknown beetle

Unknown beetle

Observation - Unknown beetle - UK and Ireland. Description: All found on leaves of yellow iris at edge of a woodland pond. Saw the blue one first, then the yellow (thought it was another species) and then the pair! These resemble the Donacia vulgaris in my field guide, but this is described as green or brassy in

All found on leaves of yellow iris at edge of a woodland pond. Saw the blue one first, then the yellow (thought it was another species) and then the pair! These resemble the Donacia vulgaris in my field guide, but this is described as green or brassy in colour. Is this another species in the same genus?