Found growing amongst various sea squirts on seaweed.
No interactions present.
Angela, I am trawling some history..
There is something not quite right about its dumpiness and warty appearance.
But you could easily be right - the best clue is the hairy opening. Your other one http://www.ispotnature.org/node/324997 looks far more likely.
Now widely accepted as >>Sycon ciliatum<<.
here's mine http://www.ispotnature.org/node/333468 which, because of its name, does not appear in Other Observations.
PS I came back and agreed - I'm pretty certain.
Lat/Lng: 50.5, -2.5
OS grid ref: SY6676