Hi Martin, it's a GoPro Hero 8 using the built-in stabilisation (Wide setting). I have a foam "windslayer" around the camera which cuts out a lot of the wind noise.
Well these thermals were being blown gently out to sea with the northerly wind. But in winter you can actually get thermals from the sea - they're called sea thermals and occur when cold air passes over a warmer sea. November is a good time before the sea has cooled down too much... Have a look for a video of mine called "North Devon Heaven" for an example...