Here is a nice little albeit incorrect mortar mounted in said bracket . I did not have a MK7 mortar on hand so i used a Spanish 50 mm .

If i were member of the crew in a Carrier i would much prefer a mortar over the 4* inch smoke discharger. A choice of smoke , parachute flares and HE . Plus you can aim and range it . You can jump out of the Carrier and bring it with you . I don’t know if it worked but in theory it’s was a good idea .