I had seen a discussion where it was said he had changed his age for the military, but i cant see why someone would need to make themselves younger and the only "military record as such that I have seen was on his wanted add in the paper.
"Escaped from Justice, on Saturday Morning, August 29, 1801, about two miles for Dorchester, on the Blandford Road, WILLIAM MANSFIELD, a deserter from the Suffolk Militia, charged with robbing James King of a silver watch. He is 22 years of age, rather sun-burnt, five feet eight inches high, smart made, grey eyes, dark cropped hair, a mark of two spots of gunpowder on his left ear, two or three moles on the left side of his face; had on a light coat, metal buttons, striped gingham waistcoat, white nankeen breeches, brown worsted stockings, and shoes tied with strings.
Whoever will apprehend him, and lodge him in any of his Majestry's gaols shall receive a REWARD of FIVE GUINEAS, by applying to the Constables of the borough of Shaftesbury, over and above what is allowed by Act of Parliament". Sherborne Mercury of Monday 7 Sep 1801.
** He was actually charged with knocking down Henry Blythsea (James King in the papers) on the King's highway.
"William Mansfield, removed from Dorset for knocking down Henry Bythsea, Esq. and robbing him of a silver watch, was sentenced at the Assizes of Somerset held at Taunton, (which) ended on Wednesday" - Western Flying Post and Sherborne & Yeovil Mercury 12 Apr 1802.