Can anyone identify these sea weeds? I think one is kelp and the bright green one is sea lettuce.
No interactions present.
likely also to be laminaria at different stages of decay. Red seaweed anyone's guess - calliblepharis possibly.
I agree with your and gramandy's IDs, except that the green seaweed might not be Sea Lettuce it could be one of the other Ulva species (I think you need a microscope to separate them...).
Perhaps in future you could post each species separately because there can only be one 'likely ID' for each post. Keep the marine observations coming; it's always nice to see more of them on the site.
I think this is Saccorhiza polyschides. The very flat, wide stipe with a wavy-curled margin towards the base would suggest S. polyschides rather than a Laminarian.
Older specimens have a large, hollow, warty holdfast which is missing in this specimen. Typically a sub-tidal species from Dorset westwards.
would be curly if S.poly - not large enough.
Lat/Lng: 50.6388, -2.3546
OS grid ref: SY750821