This is quite petty, but we strive for completeness, yes? The British 23rd Regiment of Foot is properly designated the "Royal Welch Fusiliers," not the "Royal Welsh Fusiliers." The archaic spelling is intentional, and among the distinctions of this storied regiment, which alas finally succumbed to amalgamation in 2006.
Also, while we're at it, HMS Somerset is properly spelt with ONE m, not two.
(I note looking at the Fusiliers in the editor, the "alias," which I cannot read because my monitor is too small, is in fact "Welch," but the unit name is "Welsh." Glad to see somebody else has eyes as bad as mine)