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Some idea of scale/size would help.
Was it in the sand of the beach or on rock or concrete/stone of jetty?
Was it alone or near others of the same type?
It's possibly Sagartia elegans (elegant anemone) of which there are a number of colour variations, but they grow in groups normally
Was between rocks on rocky shore, the span of the tentacle shown was 3-4cm. It was the only one I saw in the general location.
The small size makes it unlikely a dahlia (unless very young) and the tentacles look a bit too slim and feathery, so quite likely Sagartia. It may be the light but the pinkness in the tentacles look a bit pale for variety rosea, but because of the pink it may not be Variety nivea. Sorry I cannot be more definite.
I believe it's var rosea, "pink/magenta tentacles" but a very pale version
Yes, me too (var rosea) see http://www.ispot.org.uk/node/347374#comment-120212
Lat/Lng: 54.087959, -4.760922
OS grid ref: SC195693