Identification needed

I took this photo today at Lea Gardens near Matlock in Derbyshire and can't find it online or in my guide books. Does anyone out there know what it is? I don't know if it is a moth or a fly. They were congregating round the leaves of several Acer trees and the ones with the long antenae were flying up and down vertically as if displaying. Some others had smaller antenae and had their wings folded 'tent like' while at rest on a leaf.
Many thanks in advance

They are one of the Longhorn moth species. Adela species I suspect. Some one will be able to sort it down to species I imagine ( I could guess but not on here !! )
Cheers
JohnR

Looking at my "British Moths and Butterflies" it looks like Adela reaumurella".

Cheers

Scott

Thanks John and Scott. I always seem to find things which aren't in my books!