I saw a Josh Gates “Expedition Unknown” whwere he was exploring megalithic structures like Stone Henge on England. North of the Orkney Islands there was what appeared to be a stone ring structure on the sea floor. This makes the it appear possible.
UK author John Christopher wrote The Ragged Edge (or A Wrinkle in the Skin, depending on US or UK purchase). It was about a massive earthquake in England that, essentially, lifted the English Channel and restored Doggerland. Book had an unfinished quality to it, but the concept has stuck in my head for years!
There is a theory that the stone circles and megaliths in Orkney were where the whole idea/culture began and then spread southward
I love stuff like this and was so relieved that all my old OOP megalithic theory tomes survived the Fire and Water
Thankfully the totes I kept them safe from mice in were a fortuitous choice.