So I finally completed the radio mic to computer adaptor today, I have filled the computer side hole with Sugru, fixed the Teensy board inside also using the Sugru and filled a small hole next to the mic socket, popped the lid on, plugged in the TTI CB mic and it worked a treat.
So, my desk mic then had a 4 pin plug fitted to the Uniden CB wiring standard and was plugged in, audio was good, though using this mic overdriven the pre-amp so it needs to remain bypassed unless a different mic is connected, I had to adjust the volume of the pre-amp on the desk mic as well as the tone, this is now done but may need adjusting again later, as it is Uniden wired it will also work with a CB radio to this standard, my TTI TCB-550 would work wonders for this.
I got a reply from another station when I did the test on GB3IR to see what the audio was like to another person, it was reported to be fine, all that remains is to get this thing aired on Echolink and see what it is like.
So a big thanks go out to KK4JDO for such a wonderful idea and I hope to work him on Echolink with it.
73 de M6RSQ