It is easy and convenient to assume that British soldiers in general were uneducated and illiterate, but it is far from the truth. Various types of evidence illustrate that these men had, in varying degrees, the functional literacy necessary to manage their personal affairs, just as we'd expect from any working-class citizen in any era. Among the realms where this is evident is that of personal finance. Soldiering in the British army was a career choice defined by contractual obligation between the man and the army, whereby the soldier received compensation in return for service. As with any job, men knew what they were entitled to and protested if they did not receive it.
In general, officers in a regiment were responsible for managing the regiment's finances and seeing that each man received his due. Because very few records of individual soldier's finances survive, we lack information to prove how well the army met its obligations to the rank and file. But other sources suggest that men were meticulous in claiming their due even in highly extenuating circumstances.
Several thousand British soldiers spent some part of their time in America as prisoners of war. Many escaped and made their way back into British lines, often after great hardship. My own estimate, based on examination of muster rolls, is that at least one thousand men rejoined the army after making escapes, often joining different regiments than those in which they'd originally served. In 1782, a board of officers in New York heard claims from soldiers who had been unable to get their full pay, clothing and other entitlements because they'd left their incarcerated regiments - and the bookkeeping that recorded their accounts - and spent time as fugitives in the American countryside.
One such man was Michael Tevin. Called "Tiffin" in some documents, he was a 29-year-old soldier in the 47th Regiment of Foot when that regiment arrived in America in 1773; at 5 feet 5½ inches tall, he was a half-inch shorter the usual minimum height for a soldier. After service in New York and New Jersey, impending hostilities brought the 47th to Boston. When that city was evacuated in 1776, the 47th was transferred from General Howe's army to Canadian service, sailing from Halifax in Nova Scotia to Quebec. Tevin went with his regiment on Burgoyne's 1777 campaign that ended with the capitulation at Saratoga.
After a year in captivity, Tevin and four other men of Burgoyne's army escaped from the stockaded prison in Rutland northwest of worcester, Massachusetts. They managed to make a quick transit, leaving Rutland on 27 September 1778 and arriving on British-held Rhode Island on 9 October, successfully evading capture by lying in the woods during the day, traveling at night, and convincing those who stopped them that they were local countrymen. They were drafted into the 38th Regiment of Foot, then in Rhode Island' Tevin continued in that corps through the end of the war.
In 1782, Tevin made his claim for pay and clothing due to him. He explained that his accounts with the 47th Regiment had last been settled through 24 June 1778, at which time he had nearly 2 pounds due to him. Also due was three years of "Queen's bounty" (a term we have not yet defined) amounting to £1.4.4½, his pay from 24 June 1778 until he joined the 38th Regiment that October, subsistence money (that is, the portion of his pay allocated for food) for a period on Burgoyne's campaign when rations were resticted, and his regimental clothing for 1776 and 1777. He accounted to the day for every penny that he believed was owed to him.
The board of officers countered some of Tevin's claims, not due to inaccuracy of his figures but because they were offset by other compensation. When Tevin joined 38th Regiment he received clothing and cash with a total value exceeding that of the money he claimed; the 38th also gave him regimental clothing that was charged to the 47th Regiment for the year 1776. Tevin acknowledged that he'd received regimentals but had considered them to be for 1778; he also agreed that he'd received three shirts and some cash, the latter a reward for escaping. The accounts were reconciled and Tevin, in recognition of his escape and effort to get promptly within British lines, was granted his claims.
When the 38th Regiment returned to Great Britain in early 1784 Michael Tevin, originally from Crossdoney in County Cavan, Ireland, was discharged from the army at Basingstoke, England. He returned to his native land where in 1793 he joined the army again, this time in the Royal Irish Invalids. He was discharged and received an out-pension from Kilmainham Hospital in 1802 at the age of 58, having served a total of 31 years in the army. He died on 20 April 1816.