Thanks. I did my usual of knocking down the saturation (-15) and upping the vibrance (+15) to lose the skin colour a touch. My other processing was just to the exposure, W & B points, WB etc. That gave me a "normal" looking portrait, still with a touch too much red so nudged down that channel's saturation. "Old Skool" was using a different split toning setup to normal: highlights @ 70 hue, shadows @ 250, both at 15 saturation. Normally I'd have them closer to the other way around (shadows being yellow/orange, highlights being blue) but this was quite an interesting "filmy" look.
My split toning almost always has the shadows & highlights set to 180 degrees apart and saturations similar (but low). I liked this effect for a change though.
Biggest surprise was NOT using the lens correction within LR. The Siggy creates a lovely natural vignette wide open which I find really works. Turn correction on and it disappears and it looks a lot more like any other lens!