Not new species but I've not seen either of them before in this location.
The first was Codium fragile sub spp atlanticum (or green sponge fingers) at Dale Fort Jetty. It betrayed its identity by virtue of its blunt utricles (not a euphemism).
The second is not in any way rare but found in a very odd place. Himanthalia elongata (or thong weed) (again not a euphemism) is usually found in reasonably exposed locations low on the shore. People who've been to Skomer in the summer will have seen its long reproductive structures as they got on or off the boat if it was anywhere near low tide. These grow from a small perennial mushroom like object. The last place you'd expect to find it is up on the middle shore at Frenchman's Steps Bay. One of my students, Elsa from City of London Girls School found it there and asked me what it was. There were even some bedraggled receptacles (the long dangly bits) on some individuals, presumably survivors from last year. I suspect the northern aspect and overhanging trees keep the shore dimmer, cooler and damper than it would normally be at this height.