This one pretty clearly keys to Kogotus, but it also looks fairly different from specimens I caught in the same creek about a month later in the year. With only one species of the genus known in Washington, I'm not sure about the answer to this ID.
Troutnut on Feb 23, 2012February 23rd, 2012, 5:00 pm EST
I don't know my UK species, and some (like Hydropsyche) might be hard to tell apart from close relatives in those pictures, but within those limitations your IDs look good to me. Hopefully somebody who betters knows the UK can chime in.
Jason Neuswanger, Ph.D.
Troutnut and salmonid ecologist