It wasn't an off-hand comment. The movie was being planned in conjunction with BBC America and even after Moffatt shot the idea down with his "I OWN DOCTOR WHO" stuff, Yates confirmed in a podcast on SnitchSeeker (I think in 2012/2013) where they asked him about Moffatt's comments and he said, no, it's still happening.

David Yates said a few years back he'd be making a movie and even after Moffatt shot that idea down, Yates confirmed that he will be making a Doctor Who movie, it just wouldn't happen for another 5-7 years. I personally would like to see that movie, mostly because Yates is actually a good director, something I can't…