I'm afraid that's cloud cuckoo land. If the NO vote wins then any discussion about a fairer system will be dead and buried for decades, which is exactly what those who the system suits perfectly (i.e. the two "big" parties) want.
Like many others, at first I didn't really know what AV consisted of, but that was because I didn't make the effort to look at what it consists of. It took me a couple of minutes to look at it, and it's clearly superior and fairer than FTOF, sorry, FPTP.
If you'll allow me to quote myself, see above, and then see that rat-face Reid has already proclaimed as much (from the BBC website):
Labour's Lord Reid, who backed the No campaign, said the decisive result "should put electoral reform off the agenda".