why did England end up with a separate Grand Lodge for the Mark in 1856

The exclusion of the Mark degree from the recognized series of degrees under the 1813 Articles of Union left it without formal standing in the English Craft system 1. While the degree possessed ancient operative roots—where stonecutters chiseled distinctive marks onto fashioned stones to identify their workmanship—the English Craft agreement restricted official recognition strictly to pure Antient Masonry, leaving the Mark degree unrecognized by the United Grand Lodge of England 1.

To provide proper governance for the lodges practicing these ceremonies, brethren established a separate sovereign authority 1. The Mark Grand Lodge was formed specifically to take under its wing those lodges working the Mark Man and Mark Master ceremonies, which were otherwise excluded from the recognized series of Craft degrees 1.

The Grand Lodge of Mark Master Masons of England and Wales was formed at its first meeting on 23 June 1856, as the Grand Lodge of Mark Master Masons records, and installed the 2nd Lord Leigh as its first Grand Master. By establishing its own independent jurisdiction, the Order preserved the Mark ceremony and provided a regular administrative structure for Mark Master Masons across England and Wales without conflicting with the constitutional limits of Craft Masonry 1.

The United Grand Lodge of England voted unanimously at its March 1856 Quarterly Communication to adopt a report from the Board of General Purposes regarding the status of the Mark degree, as an article on the Mark Masons' Hall website records.

The adopted report declared the Mark degree to be a graceful appendage to the Fellow Craft degree. It concluded that the degree formed a link between the second and third degrees of Craft Masonry, was not at variance with the ancient landmarks, should form part of Craft Masonry, and could be conferred by regular lodges under the sanction of the Grand Master.