Wonderful video lc. I wouldn't call this old school though, in fact just the opposite. It was about the early nineties whe, at least as far as I'm concerned, curries took a turn for the worse and there was a noticeable deterioration in quality.
Certainly I'd never had a sour madras before that time and I notice yours includes both tamarind and lemon juice, so distinctly new school from my perspective.
That said it's an exemplary curry you made in all other respects.