At https://www.livescience.com/animals/extinct-species/giant-82-foot-lizard-fish-discovered-on-uk-beach-could-be-largest-marine-reptile-ever-found … it was in fact a very large ichthyosaur that lived in the seas of late Triassic – going back 200 million years ago. It appears to date around the time of the Triassic mass die-off event, terminating that period and ushering in the Jurassic. It was discovered by a man and his daughter walking the beach at Blue Anchor in Somerset. This is more or less situated in the Severn estuary. The sediments in which it was found indicate earthquakes and tsunamis were occurring at the time. The geology is known as the Westbury Mudstone Formation – on which you can find out more about on Wiki.
The same story is at https://www.sciencedaily.com/releases/2024/04/240417182659.htm … which used the same press release it seems.
Over at https://www.livescience.com/animals/snakes/50-foot-king-of-the-serpents-may-have-been-the-biggest-snake-to-ever-live …. equally, it may not have been. A giant snake, going back 47 million years ago to the Eocene, was dug out of a lignite mine in India. The fossilised snake was an estimated 50 feet in length. Note – the Eocene was between 56 and 34 million years ago on the geological column. It began with a catastrophe and ended in a catastrophe.