This did some searching, but as for 1796.. the closest I was able to find was 1800 in conversion charts.

in 1800 55 pounds was worth $1,796.35 in 1970. this was so far the earliest conversion I could find,,, the 1970

taking the value of 1970 and today's worth of the pound, which is $1.83 american vs pound.. you come to $3,287.32

a shilling was worth 12 cents in 1971