Studio Green is that gorgeous near-black green — dark, broody, almost reading as black until the light catches it and the green sings. Getting it out of a Dulux tin is doable, but be realistic: nothing in Dulux's range lands bang on it.
Your best bet is Dulux Scottish Loch (LRV 7.5), which comes in at ΔE 3 from Studio Green. That's close but not imperceptible — under ΔE 2.5 we'd call a colour a true match, and ΔE 3 sits just outside that. In practice you'll get the same deep, almost-black green character, though side by side a keen eye might spot a slight difference in undertone.
The runner-up is Dulux Cannon Ball (LRV 8.5) at ΔE 4.5. That's a noticeable step further away — fine if you like the colour in its own right, but I wouldn't reach for it expecting a Studio Green stand-in.
Here's the honest bit, mate: Studio Green's magic is partly in F&B's pigment depth and the way it shifts between black and green across the day. Dulux's emulsion is a perfectly good paint, but the chromatic richness of the original is hard to replicate. If you're matching to Studio Green because you love it, my advice is just buy Studio Green — for a near-black green you typically only need it in one or two rooms, so the cost difference is small.
If budget genuinely rules and you're going Dulux, take Scottish Loch. Buy a sample pot, paint two coats on a large bit of lining paper, and live with it on the wall for a couple of days — north-facing it'll read almost black, south-facing the green wakes up. With colours this dark, an off-white or grey primer underneath helps you reach full depth in two coats rather than three.