Confidence: I'm as sure as I can be.
Notes: H. radiatus and H. digitatus are similar in size and can both be found on rivers in October. Under the suggested species, on page 147 of 'The adult Trichoptera of Britain and Ireland' by Barnard and Ross (2012) it says that the dark speckling in the apical forks forms well defined long streaks. Photographs are provided and the pattern on the wing of the above caddis matches that of radiatus, on digitatus the dark markings are much less well defined and are more blurry. This one was found at rest on a willow leaf by a small river.