They are a type of Hatch Hinge for boats.
Glad I could help, have a happy trip sirI know most of you hardly have slept, worrying about the hinge dilema.
But worry no more, I followed the advice from JonnyHistory and got myself over to the RS website, and Bingo, a pair of stainless steel offset hinges that look like they were made for the job. Also a perfect excuse to use the riveter which has laid dormant for 10 years in the garage.
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Off to Scotland tomorrow for a weeks pike Fishing on Loch ken. Happy Days.