It looks like the stem piece of something rather large and interesting. It's a very weird idea to fit the line of brickwork round the shape, but in the best tradition of beachcombing to use pieces of old wreck in building a house.
I have used a smaller stem piece as a bracket to support a projecting bay window in my cottage, but it is only about 3 feet long, not this monster.
Don't tell me that Malwen has come to grief! She was for sale not very long ago (could be a few years, time flies the older you get). Remember also seeing her on her mooring on one of my visits to West Mersea - my late mother used to like me to take her there for lunch.
No, Malwen is fine, on the south coast somewhere according to a previous owner. She was built close to this building and apparently the first go at the forefront didn't work. So they redid it and the old forefront ended up in this building. Although the scarf has opened in the 60 odd years its been in the building, it's difficult to see what was wrong with it.
As you might have gathered I am an MG fan. I have an Eventide 26 built by Hartwells in Plymouth (according to the first owner, the first to be built properly to the plans) in 1963. I have owned it since 1980. I met MG several times in his later years and have all his books, most signed by him. Happy memories.
Although brought up in Essex (well, Romford) I was told as a boy that anybody east of Brentwood stiill painted themselves with woad, so only discovered Mersea when I got into boats. Attended a couple of Eventide events in the Yacht Club including the presentation of the MG seat.
Always fancied a Solani class after going on Sea Pie (page 68) in Poole about 20 years ago. However got seduced by the eastern Med so big boat money went into a super Bavaria (but not a match for Tranona in satisfaction)