Out of interest I did some web-searching about original
non-golf "Redan's".
Apparently it's a French word meaning a V-shaped defensive projection pointing towards an anticipated angle of attack.
I tried to find an old map showing the position of the Redan at Sevastopol/Crimea, which I understand inspired the term as used for the 15th hole at North Berwick.
The map - below - shows the position of The Redan. It also shows a Little Redan. Both project outwards, not in a strict V-shape, but at least outwards towards an anticipated angle of attack. I had hoped to find a more detailed close-up map or a sketch or a drawing or painting but alas no such luck. More web-searching one day maybe.
Using Bing/Google sat-maps it is possible to roughly establish where the two structures were, both seemingly at the end of rocky outcrops with steep sided valley's below.
Structures termed "Redans" were also used prior to the Crimean War, eg Wellington-Napoleon/Peninsula War, Nepoleons-Russian Campaign, but I guess there was no British golfing officer around at that time, unlike John White-Melville, who is supposed on his return as describing the 15th (then the 6th) at North Berwick as similar to the defensive fortification he saw at Sebastopol/Crimea.
The wonders of the web. A few minutes pushing keys rather than hours spent in a library.
atb