You certainly have done your homework, one little thing, I can't beleive I am going to be correcting you! "the Britons" actually just call it edible crab or brown crab, we Guerns!! call it chancre.
Now if you want a truly local local dish which you will not find in England or France check out our
Ormers!!
http://www.bbc.co.uk/guernsey/conten..._feature.shtml
Stuart