Let me be straight with you: Edward Bulmer's Invisible Green is one of those colours that's tricky to replicate on the cheap, and the numbers back that up.
The nearest match we've measured is Dulux Celtic Moor 2 (LRV 35.4) at ΔE 5 from the original. To put that in plain terms — anything under ΔE 2.5 is what I'd call a very close match, near enough indistinguishable on the wall. At ΔE 5, Celtic Moor 2 is in the same family but it's a visibly different green. You'd notice it side by side, and you'd certainly notice it if you were trying to touch in against the real thing.
The other options drift further still. Crown Evergreen Echo (LRV 27.5) lands at ΔE 11.9, and COAT Park Life (LRV 31.8) at ΔE 13.8. Those aren't matches — they're just greens that live in roughly the same postcode. Park Life is a lovely colour in its own right, mind, and COAT is a genuinely good water-based paint, so if you're flexible on the exact shade it's worth a swatch.
Here's the honest advice: what makes Invisible Green special is that it's an Edward Bulmer natural paint — earth-pigment colour with real depth that shifts beautifully with the light. That quality is part of why it costs what it costs. A standard acrylic in a near-enough green won't give you the same living, changeable feel. If it's that specific Bulmer character you're after, no Dulux tin is going to fully deliver it.
So if budget is the deciding factor, order a Dulux Celtic Moor 2 sample pot, paint a big A2 board and live with it for a few days before you commit — you may well be happy with it. But if you fell for Invisible Green specifically, save up and buy the real one. You'll only end up disappointed chasing a £30 dupe of a £60 colour you actually love.