Cracked it !! My cold swimming continues but there was one drawback, Brain Freeze, the intense though short lived pain across the forehead caused by the temp of the water (8C today).
I had an all over head and neck rubber hat for a long time but didn’t use it because it was too difficult to get on and off. Resurrected it the other day by cutting the bottom bit off and using it has a headband. Helped a bit but not the answer, so then donned the now shortened remnant and that cut the pain out, so it must be the head that needs protecting. But then I couldn’t get a good seal with the goggles and I do need to see where I am going because of the rocky shapes of the sides and the floating rope ladder by which I abseil in.
Final throw off the dice today, I cut it again, drastically, from the top of the face opening so that it sits tight on top of my ears but leaves a space for the goggles to seal.
Eureka, all set for swimming all winter…I hope.