We have just returned from a week at the property and cannot recommend Halki Sea House highly enough.
Eleni and Stegos are truly wonderful hosts and everything from booking, communication, greeting us on arrival etc etc was seamless.
The house itself was amazing and its location in Halki could not be beaten.
We walked to all the main beaches on the island but if we're honest there's no point as the swimming directly from the house is way better.
All the restaurants in Halki are very similar but whichever you choose have the Halki Shrimps.