Claim: Sir Christopher Wallace was appointed as Lieutenant General in the Chief of Joint Operations (appointment held by the 3*-ranked Officer that leads PJHQ, the British tri-service headquarters from where all overseas military operations are planned and controlled) on April 1996; while Sir Ian Garnett was appointed as Vice Admiral on February 1999.
Evidence: Major General Christopher Wallace led the team that began establishing the headquarters from 1994. The Permanent Joint Headquarters was established on 1 April 1996 to enhance the operational effectiveness and efficiency of UK-led joint, potentially joint and multi-national operations, and to exercise operational command of UK forces assigned to multinational operations led by others. Wallace was appointed as CJO in the rank of lieutenant general. Sir Ian Garnett Vice Admiral February 1999 The Permanent Joint Headquarters (PJHQ) is the British tri-service headquarters from where all overseas military operations are planned and controlled. The Chief of Joint Operations (CJO) is the appointment held by the 3*-ranked Officer that leads PJHQ. 
April 1996 Lieutenant General Sir Christopher Wallace February 1999 Vice Admiral Sir Ian Garnett The Permanent Joint Headquarters (PJHQ) is the British tri-service headquarters from where all overseas military operations are planned and controlled. The Chief of Joint Operations (CJO) is the appointment held by the 3*-ranked Officer that leads PJHQ.