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Angela - a lovely picture. I am wondering whether the bright orange is another organism altogether. What you describe is perfect of course, it just seems a bit bright and only one. The animal in the second picture is far more typical.
The picture is a whole delight. Two sorts of cowrie (I suspect) both forms of Trivia.
And the sponge Sycon ciliatum.
Another squirt possibly the reddish Ascidia mentula.
Maybe the Sea lemon nudebranch Archidoris pseudoargus
I've returned, refreshed from a summer's study. These grey squirts are not easy, very rarely conforming to descriptions.
I have no doubt about this one - "soft, translucent gelatinous test", "transverse bands of muscle in body wall" smooth, uniform colour, hints of strong yellow ("delicate yellow margins") on the siphon. Exhalent siphon just posterior to inhalant - perfect. The diagram on P437 Fish&Fish** fits perfectly.
**A student's guide to the seashore - http://www.amazon.co.uk/Students-Guide-Seashore-J-Fish/dp/0521720591
Lat/Lng: 50.5, -2.5
OS grid ref: SY6675