It's at the Museo della Motorizz. Militare della Cecchignola, Rome (Italy)
http://the.shadock.free.fr/Surviving_British_Early_Armoured_Cars.pdfthis site also shows pics of two other Triotas in Northern Ireland, very similar vehicles but different headlights and extra sidelights on the other. if they're not the same vehicle in different states of restoration they must be sister vehicles.
Guy