Would you still need another standalone AV program??
Like AVG/Avast etc?
I spose you would, since Comodo’s AV wouldnt scan emails as well would it, like AVG/Avast etc?
I would. I prefer to scan on the fly when a virus tries to enter the computer, rather than detect and remove them when they try to run. The main purpose of the on demand scanner is support the installation of CFP-to select clean PC mode and Train With Safe Mode for FW and D+, Comodo would like to help you be sure that you really are currently virus free-nothing waiting to be executed. But of course you get the added benefit of an on-demand scanner that you can use anytime. 
I havent installed the latest version yet, but is the on-demand scanning on permanently? While the firewall is running?
Or only enabled while its installing the firewall?
So, I take it this (the scanner) wont conflict with any other AV program then?
If both are running at the same time
WHAT does it do exactly, something similar to Boclean?? scan in the background for nasties, or something?
You can use it anytime, but it is really not running except for at those times. Kind of like going to an online virus scanner to check on your system, but you have the virus signatures on your computer instead. No interference, since it isn’t running on your real time streams, but scanning the stuff you have already installed. Probably shouldn’t do yet another on-demand scan while it is running, but maybe even that would work. 
Cool Sded! Thanx for the explanation / info