People do still anchor
around some of the islands, especially Oxia, which has long been used by yachts transiting from the Gulf of Patras to the Ionian
, and that's unlikely to change now that the Emir of Qatar has bought some of the islands.
Probably like Skorpios (ex-Onassis and now owned by a Russian heiress), you'll only be impeded from anchoring
if the Emir's minions buoy off the anchorages
. Even on Skorpios, though, that doesn't always work
As for Astakos, there are a couple of small supermarkets and a good greengrocer there. Look at the entry on the World Cruising Wiki for details of the harbour. We had no poo pongs on our visit - Preveza town quay is usually much worse.