I knew someone would know. Thanks I met a lovely old chap a few years ago who worked on VHF NTSC Colour at the BBC. He remembered how good it was.

By the early 1960s NTSC was a lost cause for a common European standard although the BBC remained an advocate almost alone (it was relatively simple & robust enough in the British environment). In the end of course there could be no achievable agreement.

NTSC straight off VT was surprisingly good, even C format. (But the faster tape speed for 30 fps* helped of course.) *Approx!