UPDATE:
(I forgot to post an update to this once I found a fix) so here it is.
I believe my problem occurred because I changed my password from the original admin password to something rather too complex, and perhaps some of the character I used conflicted with the character set recognised by the software / firmware. In any case the advise that I received from my (very helpful) Chinese seller, from his contact at Dahua, was that it was impossible to reset the password without opening up the camera. Sounds drastic, but with the right size screw drivers it is in fact very simple.
1. Remove the 4 screws that hold the 'ball' (main body of camera) into the base, you can locate these screws by turning the camera upside down, and turning the base (screwing action) until you see each screw individually.
2. Once the base is removed, you can then take out the ball, and again you will find 3 screws that hold the ball together, remove those screws and open the ball.
3. Now you are inside the camera itself. Look at where the microphone wires conect to the circuit board and you will see a black reset switch next the mic contacts.
4. Now plug in the camera so that it has power. And once powered up, press and hold down the reset switch for 10 seconds.
5. Thats the hard reset done, everything has now gone back to default. However, I would recomend that you dont yet put the camera back together. First connect to it using the camera web interface http:\\192.168.1.8, login with admin:admin, and the first thing you should do (on all your camera's) is create a new user with admin privalages, just incase you forget the admin password or have issues with it in the future.
[A small side note: After reseting my camera, I found that the Dahua software could not find it on my network, which is 192.168.0.x rather than the camera 192.168.1.x range. To fix this I had to change the IP address of my laptop to the 192.168.1.x range and then the software picked up the camera, I then changed the IP address of the camera to that of my network, and all was good].
6. Now that you are confident that your camera is successfully reset, put it all back together, and the jobs done.
It all sound very long winded, and believe me, trying to acquire all of the above knowledge took a lot of messing about, but if you follow the instructions you'll be done in about 30 minutes.
