Dylan
I help run the Waldringfield History Group and have seen many old charts and maps, but have never seen a name for the island.
Other background for your excellent video series:
The village has an industrial history. It was an important centre for coprolite mining in the latter half of the 19th century. Coprolite is fossilised mammoth dung and was sold by Fisons . There was an active barge trade.It became uncompetitive when guango was imported and the introduction of chemical fertilizers
After, the demise of coprolite, a largish brickworks was set up on the site of the current boatyard. It was not a pretty site. Let me know ifyou want some photos. It closed in the early 1900's and re-located to Blakenham, near Ipswich and eventually became Blue Circle cement.
The terraced cottages, next to the Maybush Inn, are still called the cement cottages.
We have a lot of information on the Maybush and an excellent copy of a Giles cartoon ( copywrite might be a problem for you hacks). Giles used to keep his Nicholson in the village
Please let me know if you want any further information.