It is a unified kingdom not a free kingdom as it is not part of a larger realm that has multiple "kings" like Great Britain during the time of Wessex, Murcia, Umbria etc. Plus the Queen wants there to be no room that there is one Queen, instead of the recent Bishopric of Eveningstar and Duchy of Tilverton with their own law books etc.

Updated
Article III.) Arabel Militia is the official Militia of the Kingdom of Arabel, dictated by the Crown of Arabel and lead by the Marshal of Arabel. Any mercenary force exceeding twenty-five members must register and receive special authorization from the Monarch or the Crown’s appointed Marshal. Recognized Noble Houses are permitted a household not to exceed fifty members. Special dispensations for an exception must be approved by the Monarch or the Crown's duly appointed Marshal and may be granted to safeguard the realm

Amended Article 5 and 6 to include
…. subject to the will of the Crown

Changed

S8 Note: Celestials contacted that do not pose a threat to the kingdom or the public may be exempt under certain circumstances, but the summoning and use of celestial beings in combat is unpredictable and dangerous and will not be allowed without crown approval.

to include it under the purview of Official Clergy

In consideration for their efforts to bridge the gap between the mortal realm and the persistent silence of the Divine: Celestials contacted that do not pose a threat to the kingdom or the public may be exempt under certain circumstances, but the summoning and use of celestial beings in combat is unpredictable and dangerous and will not be allowed without crown approval.