If you're after Edgecomb Gray in a Dulux tin, Antique Map is your colour. It lands at ΔE 1.4 from the original — anything under 2.5 is a very close match, and 1.4 is close enough that you'd struggle to tell them apart on a wall. LRV is 63, so it sits in that bright-but-grounded greige zone Edgecomb Gray is loved for.
The other strong contender is Weathered Pebble, also ΔE 1.4, but with an LRV of 67.7 — so it'll bounce a touch more light around the room. If your space is on the darker side, north-facing or a bit hemmed in, Weathered Pebble might actually serve you better than a literal match, because it'll lift the room without going cold.
Here's the thing about Edgecomb Gray, though: it's a chameleon. It's a warm greige that leans grey in bright light and creeps towards soft beige in lower light. Both Dulux matches will do the same dance, so don't be surprised if your samples look different morning versus evening. That's the colour working as intended, not a dodgy batch.
Test before you commit. Greiges are the trickiest family to judge from a fan deck — undertones only show up properly once paint's on the wall in real light. Get sample pots of both Antique Map and Weathered Pebble, paint two coats on A4 lining paper, and move them around the room across a full day. Look at them against your skirting and your flooring, not just the bare wall.
If you've already got Benjamin Moore elsewhere in the house and want exact continuity, stick with the BM tin — the match is excellent but no cross-brand match is ever 100%. If it's a fresh scheme and you're buying Dulux for convenience or price, Antique Map gets you there with no compromise worth worrying about.