Confidence: I'm as sure as I can be.
Notes: The Adult Trichoptera of Britain and Ireland states the following regarding L. elegans: "Very distinctive wing pattern with long dark and pale streaks/ present in Ireland; raised bogs and fens". This was found on the car windscreen on a road through upland bog with slow drains nearby and a large reservoir too. Unfortunately I didnt measure its length but it was the same dimensions as the more commonly encountered L. lunatus, its better known relative. After comparing it to the other limnephilus species the wing pattern does appear to be distinctive as suggested by the book.