You think the Brits will hold a public “beheading” for the executioner if they catch him?
I doubt it. What they should do, is have the bastard sit on the dirt and take a rifle and stick in into his neck several dozen times. Pull the trigger and it goes "click" every time. Then stick a blank or two in the chamber for the noise effect.
Then, get in front of the bastard, dip a bullet into bacon fat and tell him, "This is for real" and make a video for all the "alla Akbars" to watch and put it on the net.
At least Henry VIII beheaded his victims with one chop. Except for the occasional execution that took half a dozen. I believe Thomas Cromwell had a drunk executioner who took half a dozen swings until a Yeoman finished him off.