I would like to understand the ethics of Patents. There is a product that is currently sold worldwide, with a patent in the US only. If I was to sell the same product (diff. logo) in the UK/EU, what are the ethical implications pls?
Patents are territorial. A U.S. patent only gives its owner rights to try to exclude others from making, selling, offering for sale, importing and using the invention in the U.S.
If there is no patent in some other jurisdiction then anyone else might be able to make. sell, etc. in that location. I say might becasue there may be some other reason that the product could not be sold (regulations, a completely different patent possibly held by a different party, etc.).
Patents are about law, not morality. However, an important part of the theory of patent systems is that the inventor must disclose how to make and use the invention to the public. This promotes progress. In your case it promotes progress immediately everywhere the inventor does not get a patent. I would not worry about any ethical issue. You can worry about the inventor having an application pending in the UK or some other patent that you would also infringe.