An open-type FCB at Titchmarsh Marina is well disguised as a wooden bungalow by the marina car park.
The fascinating story of how it got there and its connection with the building of Titchmarsh Marina, is recounted on the Concrete Ship & Mulberry Blog.
Another open FCB was at Titchmarsh Marina, but is now (2023) at Foundry Quay: named the Lady of the Twizzle, it has been converted into accommodation. The story is told in detail here ‘Lady of the Twizzle’ – Walton-on-the-Naze – Essex (thecretefleet.com)
One PCB is also at the quay.
… there is also a closed PCB on the west side, up a small creek.
This makes five concrete barges in the Backwaters altogether.
There is another adjacent to Harwich Town Sailing Club which is now a breakwater.
There are four open FCBs at Burnham on Crouch and more at Rainham.
The Open Barges forming the Horsey Breakwater are metal Thames lighters.