I doubt the original recipe would have had a single step mash as that is a more modern technique that didn't become popular until around 1850 or so (later in London). Also, the 10 minute addition is very unlikely, the hops would probably be boiled for the whole three hours, but some dry hops might have been added to the cask later on.
Here's one recipe I have from a manuscript from 1778-1797 (Imperial measures):
"Flack of Reading Receipt for brewing strong Beer
18 Bushels Malt
18 pounds of hops to 112 Gallons
Boil 3 hours
For Ale
12 Bushels Malt
9 pounds of hops 80 Gallons
Boil 2 hours
To stand in the mash Tub after mash 3 hours"
Beer as we can recognize today but nothing fancy. By the way "receipt" simply means "recipe".