SatBilly - Thank you very much fella for your help as you just switched on a light bulb in my head. I remembered something in the menu when I previously used to use OpenVIX in that there was a signal strength meter option in which you could enter the transponder details and it would show if there was a signal being received.
Having switched from a VU+ Solo2 to a shiny new Technomate TM-Nano2 Super and using the OpenPLi 3.9.7 4D Image I had a look and found the same option, for those that would like to know how to use this option in case of similar problems, here goes:
Press Menu - Setup - Service Searching
Select Satfinder - Tuner A or B (whichever your using)
Now you should see an info screen appear with some SNR and AGC signal strength meter bars
Using the down arrow on the remote, scroll down to Frequency and change it to the frequency to test (in my case it was 12520)
Move down to Polarization and change it to either V or H depending on what the transponder should be set at (in my case it was V)
Move down to Symbol Rate and change it to the rate of the transponder (in my case it was 22000)
Now if you see a SNR and AGC percentage bar moving up and down a little then it means your receiving that particular transponder ok
This is where the problem was as I was not receiving any SNR and AGC percentages (they were showing a solid 0%), so I wondered if the Frequency was slightly out on my box and hey presto I changed the frequency up slightly from 12520 to 12522 and I started getting a variable 65 to 70% on the SNR and on the AGC I was getting between 82 and 86%.
I then realised that my box could be slightly out on that transponder so I used Dreamset and edited the transponder frequency from 12520 to read 12522 and then uploaded the settings to the Technomate receiver, rebooted and hey presto CNN, Boomerang and Cartoon Network came back !
I must have gotten confused as I doubt now if I would have received CNN yesterday, it was most probably before yesterday when I had it running ok on a VU+ Solo2, now having changed to the Technomate TM-Nano2 Super, the receiver is probably slightly off frequency for some reason, I don't know, maybe someone will be able to clarify that.