Storms provide the most dramatic images, but Cliff Erosion has destroyed much of the island over the centuries.
Shingle drifts towards the Medway. It builds up on one side of groynes and obstructions creating drops of several feet in places. Plants are getting a foothold on some of the higher shingle banks. Although most of the island is prone to sea flooding, the lowest areas are also at risk from other sources.
Much of Sheerness as well as Sheppey is below sea-level and so is prone to flooding. You can find references to this as far back as Samuel Pepys, when he was responsible for dockyards and was choosing sites to defend the Thames.
Parts of the current sea wall around Sheerness was built following the 1978 floods. I believe The sea wall along Marine Parade was built in the 30s following flooding in 1927. It was raised and strengthened after 1978. A shingle bank was created between Bartons Point and the Leas, I believe in the 60s.
The sea wall between Bartons point and the white house was build by Mowlem following the 1953 floods. There is an excellent book commissioned by the Essex County Council called "the Great Tide" which details the causes and effects of the '53 floods. The same floods caused the building of the sea wall from near the Dockyard to Queenborough. I believe this was one of the breached sections.
The site of St. James church now lies a few hundred yards out to sea though contractors were hired to remove the remains since they were hazardous to smallboats. There are records to indicate that St. James replaced an even earlier church built about a mile 'down the road' which disappeared in Tudor times. Before that I have no idea, though I can see why the Romans would have had a large garrison helping to defend the approaches to the River Swale and the Isle of Thanet.
Other communities have been lost but at least they leave behind ruins to excavate. All that could possibly be detected now is a ribbon of debris stretching towards the North Sea along the route of the roads which must have also existed.
Would anyone keep titles of land that no longer existed. Maybe the descendants of the Goodwins could answer that.