This video from Ireland says about itself:
From Wildlife Extra:
June 2011. One of the largest ever known gatherings of Fin whales in British waters has recently been observed in the Celtic Deep, 50-70 nautical miles off the coasts of north Cornwall and south west Pembrokeshire. On the afternoon of the 21st May, some 21 Fin whales were observed in the Celtic Deep, with the gathering of whales extending over at least ten miles of ocean.
Update, from the BBC:
Scientists have described whale sightings off the Cornish coast as one of the “largest gatherings” of the species ever seen in British waters.
Researchers spotted 21 fin whales 50 to 70 miles offshore, feeding near the surface over 30 minutes.
Humpback Whales return to the Dingle Peninsula: here.
Stranding records are faithful reflection of live whale and dolphin populations: here.