Be honest with yourself here, mate — there isn't a tight Dulux match for Edward Bulmer Invisible Green. The nearest two are Dulux Celtic Moor 2 (LRV 35.4) at ΔE 5, and Dulux Moorland Magic 2 (LRV 35.9) at ΔE 5.4. Both sit above ΔE 2.5, which means the difference is genuinely visible side by side, not a rounding error.
The reason it's tricky is that Invisible Green is an Edward Bulmer signature — a soft, muted, slightly grey-leaning green built on natural pigments. That earthy complexity is exactly what mass-market formulations struggle to replicate. Dulux's greens in this bracket tend to read a touch flatter and cooler, which is where that ΔE 5 gap comes from. Celtic Moor is the better of the two to my eye because it holds onto a bit more of the warmth; Moorland Magic leans slightly more towards a clean, modern green.
Now, the obvious "but what about the cost" question. Edward Bulmer is a premium, plant-based, low-VOC paint, and part of what you're paying for is that pigment depth and the breathable finish. A Dulux match at ΔE 5 will get you in the right postcode for a fraction of the price, but it won't give you the same quiet, lived-in quality on the wall — especially in a north-facing room where Invisible Green really earns its keep.
My practical advice: order both Dulux sample pots, paint two coats onto A4 lining paper, and tape them up next to the Invisible Green swatch on the actual wall. Look at them in morning and evening light over a full day. If you genuinely can't live without the Bulmer character, just buy the Bulmer — at ΔE 5 you're compromising, and you'll know it. If you only want the rough colour direction, Celtic Moor 2 will do you proud.