Final answer:
King Henry I is traditionally credited with establishing the Exchequer, a central government accounting office, between 1107-1108 as part of efforts toward centralized government and effective taxation.
Step-by-step explanation:
The central government accounting office, known as the Exchequer, was established during the term of King Henry I between 1107-1108. Despite the detailed discussion about various aspects of the British governmental reforms and administrative measures in the provided reference content, there is no direct mention of who exactly devised the Exchequer. Typically, it is understood that King Henry I is credited with the institution of the Exchequer to oversee the royal finances. This development was part of a broader trend towards centralized government and effective taxation during that period, which included the creation of various administrative bodies and regulations, such as the Treasury Board and the Privy Council.