Native to the mountain ranges of Afganistan east to Taiwan Clematis montana seems equally at home in British gardens mountain or no mountain. Generally it’s appreciated for its flowers in springtime and otherwise overlooked, however if you have resisted cutting it back after flowering you might be lucky enough to appreciate the seed heads (aka the achene). Not dissimilar to your ‘dandelion clock’ each seed has a wind catching tail to float it off to somewhere else on the mountain (or to someone else’s garden). Seen here in January.
Tend&Grow 