Island of Kos

You may have better luck inquiring on Trip Advisor, because of its many British contributors... Kos is a favorite island with UK, because of direct fllight s and also package tours available... you'll get lots suggestionsl.

I would have recommended buying a travel guide, unfortunately, these guides generally describe listed places as being more or less interesting depending on each reader's preferences. But since they don't know each reader personally, they let them choose what will be their "best."

However, I agree with Janet, especially since Trip Advisor is great because it lists the "Best" for every place in the world for you, whatever your tastes and preferences. :)

You might enjoy a day trip to the tiny nearby island of Nisyros, which has an active (but not erupting) volcano that you can walk around inside.

You’ll see steaming fumaroles and walk on soft, warm areas. We found it fascinating— like walking on the moon. Wear closed shoes (not sandals). There are also picturesque villages & two small ports, & a visitor center with a short film showing how the island was formed.

Kos’ Old Town has an incredible castle on the waterfront and a lot of archeological ruins nearby.
Great beaches just north of town including Lampi and Atlantis.

We rented a car for a day and drove to many of the beautiful beach towns including Kefalos—which had ancient temple ruins overlooking one of the most beautiful beaches on the island.