So this was a real adventure for me but it appears to have worked. I swapped the daughter board after I had cleared the 2 spiders that were inside. This went quite smoothly for me considering I've never done anything like this before. Then when I was looking at the other one I saw that the controller lead was tucked under the power switch on the other one which seemed neater so I decided to do this on the one I was putting back together. Big mistake! Because I unscrewed this the power switch which made the switch stop clicking so I took it out and it came apart. Panic mode set in, I thought I had broken it so I was considering swapping it out for the other one but it is all connected to other bits. I thought it was game over but my amazing wife took over and managed to fix it for me.
We plugged it in and voila! The colours are perfect now on the console that works but had the output problems.
It's been a bit of a journey but finally I'm back playing my intellivision as I remember it.
Let the good times role.