The latest version of software for your unit is 1.00.26, This has been broadcast numerous times, and your unit should have downloaded it if left in standby overnight.
It is currently on air until 10 am tomorrow – 8th June.
Instructions on how to manually update can be found in this FAQ
It records 75% of the programs that it is set to do, but often refuses to record random programs like coronation street.
I have had a look on a couple of forums and think that maybe I need to upgrade the firmware, but I don’t have any cables.
How can I receive an OTA software update??
First tell us what software version the box is currently using. My gut feeling would be that the most likely problem is that the box is not properly tuned see the third post in the following thread http://myhumax.org/forum/topic/pixelating-channels-34-5-on-9300t