Euconomelus lepidus

A small but distinctive planthopper associated with Spike-rush, Eleocharis palustris.   The front parts of the forewings are pale and speckled with dark spots, and there is a dark brown band across the hind part.  The forewings in both sexes have white patches along the hind margins, giving a scalloped look. The keels on the pronotum and vertex are pale, and there are pale bands on the front and mid tibia. 

Conomelus anceps also has speckled forewings, but does not have the distinct white patches along the hind edge of the forewing

A photograph showing the white patches on the margins of the forewings is needed.  Also note the habitat and associated plant species

Margins of water bodies, flushes, springs and other wet places, with Spike-rush

Local (ref.: UK Auchenorryncha checklist 2021 on British Bugs website)

Scarce

https://www.britishbugs.org.uk/homoptera/Delphacidae/Euconomelus_lepidus.html