Have always thought that mirror sqns should have been the way to do it from the start. Changing now after 12 years will take some of the Luddites out of their comfort zone and no doubt that the transitional phase will be tricky if not well managed. There have been those who think standardisation will be out the window with 2 sqns teaching the same syllabus - I don't recall this being a problem when I went through basic JP training at Syerston - 2/3 sqns there, similar number at Lynton and Leeming and 1/2 at Cranwell, all teaching to the same songsheet.