Neophilaenus can be separated from Philaenus by the straight costal margin along the basal part of the forewing (i.e the front part of the lower margin when the insect is viewed from the side).

Length 5-7 mm. A brown froghopper found on grasslands, with a relaively plain forewings and a pale line along the costal margin; there is usually a dark streak above this. 

Provided good photographs in he field or from a specimen; these should show the pale line along margin of forewing.

A grassland species

Adult: June to November

Sometimes overwinters as an adult

Common. (ref.: UK Auchenorrhyncha checklist 2021, on British Bugs website)

Common

https://www.britishbugs.org.uk/homoptera/Aphrophoridae/Neophilaenus_lineatus.html