Phoenicians from Canaan probably no.
Carthaginians, maybe.
It would be probably little more than a trading post in Cornwall, though, or perhaps in the Scilly Isles.
Very interesting cultural effects I think, quite limited direct political impact.
Though the place might swell to some degree attracting other Carthaginians is the Punic Wars go like OTL (I don't see any reason for them not to).
There might be some introduction of Punic culture into Britannia, that could make things interesting in the future.
Nothing really major I guess, though accumulating differences would make the world unrecognizable anyway by 2013.