Confidence: It might be this.
Notes: As it is a caddis which doesnt seem to be recorded yet in Ireland, this one is possibly just a species which shares some characteristics with Allogamus auricollis. This caddis has a length of 15mm, Allogamus auricollis has a wing length of 12-16mm so size is ok. Barnard and Ross 2012 says- "dark brown with darker pterostigma and pale spot at thyridium." This appears to fit and the wing venation looks like a very good match. The fly was found very close to a stony river which is the correct habitat. If there is another species so similar in size and appearance with a conspicuous pale spot at the thyridium I have overlooked it in the book?