Starting a separate thread for this, as it seems important. Discussion of previous proposal (at Straiton) is here: http://citycyclingedinburgh.info/bbpress/topic.php?id=15798
After the Straiton proposal was rejected (although possibly there's still an appeal to come?), the plan is now to build the studio north east of Dalkeith: https://variety.com/2019/tv/global/major-scottish-film-and-tv-studio-near-edinburgh-in-the-works-1203102851/
NCN 1 currently goes right through the middle of that site.
There's a public meeting at Woodburn Primary School on 31st January, between 4pm and 8pm.