Andrew & Viking,
Thanks for the replies. I have had no problems running mythtv-setup itself; I was able to access this from the computing menu after following Tim's advice regarding the avenard repo.
With respect to configuring the backend properly, I have gone through exactly the same process that I did in 0710...
1. I changed the format to "PAL" and the broadcast(?) to "europe-west" (I'm in the UK).
2. I added the 4 tuners (I have x2 KWorld 399s) with no problems
3. Sources - I made an EIT jobby
4. For each of the tuners, I linked it with the EIT source and did a channel scan, which I watched like a hawk and saw all the various channels pop up as it was scanning.
Then, I ran "sudo mythfilldatabase" on the KDE desktop, and then left it overnight just to be sure everything had finished doing it's thing, and it didn't work. Have I missed something?
@Andrew, the only other thing I'd mention (not that I think it's relevant, because my tuners appear to be working) is that before I plugged in my tuners, I tried to install the "v4l2-firmware_0+hg20090324-1_all.deb" that you sent me, but it didn't work as it was conflicting with "linux-firmware". After, I installed "v4l2-modules-source_0+hg20090324-1_all.deb", which did work. However, myth was not recognising my tuners. So then I put "dvb-usb-af9015.fw" (downloaded from the linuxtv wiki) in /lib/firmware/, which made myth recognise the tuners. Could any of this be causing problems?