Empire Grey No.171 is one of Mylands' warm greige-taupes — a grey with a soft brown warmth running through it, so it reads gentle and grounded rather than cold. If you want that look in a Dulux tin, two colours get you there.
Dulux Bleached Lichen 1 (LRV 34.5) sits at ΔE 2.3 from the original. Dulux Iced Frappe (LRV 33.8) matches it at ΔE 2.3 too. Both are well under the 2.5 threshold I'd call "very close" — meaning side by side you'd see a whisper of difference, but on a wall, in a room, nobody's clocking it. The LRVs are near identical to each other, so light bounce won't differ in any meaningful way between the two.
Which to pick? At this level of closeness the numbers can't split them — the deciding factor is how each sits in your own light, against your floor and your furniture. One will feel a touch warmer in your room, and only a sample will tell you which. That's not a cop-out; it's how tight this pairing is.
Now the honest bit: a colour match gets you the hue, not the paint. Mylands trades on depth and marble-dust pigment density — their finishes have a particular richness that Dulux's standard ranges don't fully replicate, especially in a low-sheen or matt across a big wall. If the budget's tight or you're doing a rental, the Dulux match is a sensible, sound call. If this is the feature room you've been planning for months, I'd spend on the real Empire Grey and not look back.
Whatever you choose, get a proper sample pot of each and paint two coats on lining paper. Move it round the room across a full day before you commit. A ΔE of 2.3 is genuinely tight, but your north wall at 4pm is the only opinion that matters.