By which time it was nearly sunset! With thanks to Rob @robz for her marvellous tip re low pov - don't lay on wet sand (as I used to), turn your back on the scene you want to shoot, bend from the waist, hold your camera at nearly ground level and shoot the scene behind you - and it works!! Cheers Rob:)
LOL FB - It's a super image, and I'm so pleased that you found the strange maneuver worked for you. I also had to laugh at the thought of more people cheerfully peering backwards... Cheers Rob