Was doing some new research and came across this:
In 1876 a troupe of French wrestlers wrestled in London. One of them was L'Homme Masque (The Masked Man). I haven't seen any earlier mentions of masked wrestlers, so this may be the very first masked wrestler in British wrestling history.
And of course this L'Homme Masque was surely inspired by the original L'Homme Masque, who caused a great sensation in Paris in 1867.
The Masked Marvel made his debut on the 18th December in Manchester and beat Angus McCheyne of Aberdeen. It was said that he had been educated at Eton, believe that if you will. He came with a promise to unmask if defeated. A few days later he defeated Norman The Butcher in 11 minutes.