Wet rippled sand on the beach at low water. Quite a concentration in one area: a few more some yards away.
No interactions present.
I've seen similar in the Gower on sand several times & took to be egg masses or 'sacs' of some sand dwelling polychaete worm. The 'head' about 1to2cm & the're anchored to the sand by a thread sunk into it. I'd guess a sand-delling Phyllodocidae species, see
.. nereids also have egg sacs that are similar to this and generally of this colour. It's a bit of nip and tuck really - hard to say without dissection or alternatively revisit and hope for a worm apppearance.
Would also be useful if you edit and move to invertebrates where other experienced users may be able to help.
Thanks to all for identifications, confirmations and suggestions. I've now incorporated the topic at the end of http://www.seahouseswebsite.co.uk/SeahousesSands/SeahousesSands.htm.
Over and out!
Mike (mhosken), if you come back and I hope you do, then your Seahouses link in the above comment os broken that's a shame. Can you fix it?
Lat/Lng: 55.5703, -1.642
OS grid ref: NU226307