Both Dulux Soft Almond 4 and Dulux Cherished Ribbon land at a ΔE of 1.6 from Farrow & Ball Setting Plaster, which is well inside the "very close" band (under 2.5). In plain terms: brush either one out next to the real thing and you'd struggle to tell them apart. Both sit at LRV 51.8, so they reflect light almost identically too — that matters, because LRV is what governs how a colour reads as the day moves around.
Setting Plaster is that gorgeous soft, dusky pink-beige — warm without going full Barbie, a touch of plaster blush that flatters skin tones and glows beautifully in north and west light. The two Dulux options capture that same warmth, so you're getting the look at a more wallet-friendly price.
Here's the honest bit, though. A ΔE of 1.6 is a tight match of the *colour*, but it doesn't replicate the *paint*. Farrow & Ball's depth comes from how their pigments and the matt Estate Emulsion finish handle light — that subtle chalky, almost velvety flatness. Dulux's standard matt is a perfectly good, hard-wearing emulsion, but it's a flatter, more uniform read on the wall. You'll get the colour; you may lose a sliver of the character. For a hallway or busy family room where you want scrubbability, that trade is often worth it.
My advice: don't trust a screen or a printed chart. Get a sample pot of whichever Dulux you fancy, paint two coats on a bit of lining paper (A2 size, not a postage stamp), and prop it against a wall — never flat on the floor. Look at it morning and evening. Pinks like this swing hard between warm and cold depending on your light and what's bouncing off the carpet and curtains.
If budget allows the real thing, Setting Plaster in Estate Emulsion is worth the premium in a low-traffic room. If not, Soft Almond 4 is your nearest, safest swap.