Dan
As I remember it the cameras were fitted in the centre and left hand side windows of the Bomb Aimers window. The Captain would be flying the aircraft so would position on the target he could see. As you say a lot of the Victors did not have glazed panels as they had been replaced with blanking plates (cheaper and lighter) when the glazed ones were u/s. Ground Crew scavenging parties were sent to the Fire Training sites at Manston and Catterick, and also the museum at Duxford, to retrieve useable glazed panels.
If were had to use them and could not get back to ASI, the brief was to blow open the cabin door and jettison the cameras. We would then divert to Rio " as the cabin door blew open while we were on an innocent Navex for training!"
If the Harriers thought it was too dangerous at 250ft at Warp speed, what chance would a Victor have had? Fortunately we never needed to try.