Thanks for the reply bak07
At the moment I have 4 tuners in my Duo2, does that mean that I wouldn't need to install any extra tuners for my present setup?
You'd be best off installing a Unicable LNB to take advantage of the FBC tuners. With 2 FBC tuners connected to a Unicable LNB you will effectively have 8 tuners available whilst only using / needing 2 cables.
This is how I understand it anyway
In fact, having just done some more reading up on it, you'd need a Unicable LNB with a splitter in order to make use of BOTH FBC tuners, without a splitter you will only be able to use one of the FBC tuners. However this is still the equivalent of 4 "normal" tuners like you currently have, albeit with just one cable coming in from the LNB.
Inverto seem to make what you'd need