Egg wrach seaweed but there may be some bladderwrack mixed in the last 2 photos.
No interactions present.
Perhaps you could move this observation to the "plants" section so that it can be compared to other seaweeds - if you click on the "edit" tab just above your observation title then you can reclassify it in the correct group :)
Lat/Lng: 55.7001, -4.9038
OS grid ref: NS176490