Prophead - I cannot see how you draw the inference that I expect no new domestic flights at all. I even wrote "unlikely to be taken up in full" in the post you are referring to.
The reason I oppose R3 is outlined in my main post. There is no reason to repeat all that, so I invite you to re-read the section on cost in particular. I also believe that a new runway at each of Gatwick and Stansted will better address the needs of London's fastest growing sector: no-frills short-haul driven by Ryanair, Jet2 etc. That is where the big demand for new SE runway slots is coming from.
On a personal note, I have four flights over the next five days with hotel stays in between. I'll continue to follow the debate with interest but I don't know to what extent I'll be able to respond in the meantime.