Likewise OpticalGirl good to talk, as some company used to advertise, now who were they....

Something that has also been put into the mix lately is Social Inclusion, the Martha Lane Fox mission you might say.
Rather than the Final Third being considered as a geographic community of interest, there is also a push from some quarters to create open access FttH networks for example that promote social inclusion in the First 2 Thirds areas as well.
I mention this as potential competition for any funding that might otherwise be directed to the Final Third - not as exactly a zero sum game calculation and rather recognising that public money is scarce (at least for non bank bail-out activities!)
I think also that we need to be careful about defining the market in terms of supply-side players and not excluding the emergence of FttH upstarts unencumbered by the baggage of incumbency - otherwise we risk distorting the market with the very taxpayer funding we are seeking to foster.
A closing thought re the Final Third - an open minded commercial analysis of the socio-demographics concerned might lead to considering the opportunity as First Third instead.... rural folks have less ready access to services and amenities than their city cousins, this makes connectivity more valuable arguably - and value drives the business case.
fibrestream, in my view the fund should invest in the areas least likely to recieve decent broadband through market forces. You can see which those are already - I made a few suggestions in my original post.
I guess this assumes that the roll out of next-gen broadband will follow the same pattern as the roll out of first gen broadband - I think that's probably a reasonable assumption.
It occurs to me that if you clearly define what constitutes the "final third", then maybe the whole question of "outside in" versus "inside out" goes away. If you're in the "final third" then you're eligible, full stop.
It's so nice not to be talking to myself any more- thanks for joining in the discussion everyone!