S.E. Chevalier Ian Sinclair KGCTpl, Worthy Grand Prior, Scottish Knight Templars, Archivist to The Clan Sinclair Study Centre

Ian Sinclair actively promoted the alternative histories of Rosslyn Chapel and Henry Sinclair

The Niven Sinclair Study Centre was established in 1999 in the Noss Head lighthouse buildings, Caithness, that was owned by Ian Sinclair, consisting of a library of books that were donated by Niven Sinclair

The statue of Jarl Henry Sinclair at Noss Head was unveiled on 30 May 2002 in the presence of sculptor Shawn Williams and the Earl of Caithness

The Niven Sinclair Study Centre was subsequently renamed The Clan Sinclair Study Centre after the property and archives were purchased by Malcolm Ian Sinclair the 20th Earl of Caithness and The Clan Sinclair Trust in 2006

Ian Sinclair formed the Prince Henry St Clair Preceptory and Commandery in 2001 and The Scottish Knights Templars in May 2004.

Ian Sinclair was also advisor to The International Order of Gnostic Templars (IOGT), founded by Andrea and Mark Amaru Pinkham in July 2005