Thanks a lot for your help. I have since managed to get the cameras and DNR-322L to work, i.e. viewed online.
1. I could not get NPAPI to work on Chrome for some reason. I went with IE which worked a charm. When it switched Java off due to security considerations, I added the various local IP addresses into the exceptions list and everything is smooth. It is a little inconvenient but I guess better a little inconvenience than not being able to get it to work at all.
2. There was an error with the initial DNR-322L installation. A separate popup window asking me to install a certain Microsoft executable file came up. Once this was installed, everything seemed to work better.
On a side note, my office network does not allow me to connect to the IP cameras via mydlink.com so I am viewing footage via my mobile network instead.
Overall I think I would still buy D-Link IP cameras again, mainly because of the entire ecosystem that it offers which I would rely on to get everything to talk to one another properly.
Downside - The software is still pretty buggy since installation features such as wireless network detection and camera detection did not really work smoothly. I dont have as much time on hand nowadays to sit down for a few days at a go troubleshooting the set-up unfortunately.