From a website I found (no idea of historical accuracy):
"RAF Coastal Command obtained a specialized derivative of the FB.VI, the "FB.VIII", which had a 57 millimeter autoloading Molins gun, an airborne modification of the light 6-pounder antitank gun, installed in place of the four 20 millimeter cannon. Two of the 7.7 millimeter Brownings were often removed in the field, with the two remaining used for sighting the big gun.
The Molins gun was adopted to help Mosquitos hit German submarines from out of range of the vessel's antiaircraft guns and proved effective, but Coastal Command Mosquitos were then qualified to carry a variant of the RP with a solid warhead. Aircrews felt the RP was a much better weapon. 25 FB.VIIIs were built, all as conversions of FB.VIs, with the first flying in mid-1943."
Not sure if a total of 25 aircraft qualifies the type for AHII or CT.