Easy one, this. Dulux Heritage Chiltern White has a near-identical twin in Dulux's standard range, and it'll cost you noticeably less.
Dulux Cotton Bloom comes in at ΔE 0 from Chiltern White — that's an imperceptible difference, meaning your eye genuinely cannot tell them apart on the wall. It sits at LRV 71.7, so it's a soft, light off-white that bounces plenty of light around. If you like Chiltern White but balk at the Heritage price tag, Cotton Bloom is the obvious answer. Same colour, lower spend, simple as that.
Worth being honest about what you're losing: the Heritage line has a slightly more refined finish and a fuller-bodied formulation than standard Dulux trade or matt emulsion. For most walls in most rooms you won't notice it. For a feature space where you want the best knock-resistance, the Heritage product earns its keep — but for bedrooms, hallways and ceilings, Cotton Bloom does the job beautifully.
If you'd rather move away from Dulux entirely, two other strong options:
- Crown Soaring Dove — LRV 75.3, ΔE 1.2. A touch lighter and brighter, still very close.
- COAT Centred — LRV 74.8, ΔE 1.7. Slightly off but in the same family; COAT's matt is a cracking finish and low-VOC if that matters to you.
Both are under ΔE 2.5, so they read as the same colour in normal lighting.
My honest steer: if you genuinely want Chiltern White on a budget, go Cotton Bloom — there's no point paying a premium for a ΔE 0 match. Buy a tester pot, paint a big patch, and check it morning and evening before you commit to the full job. Off-whites can swing with the light, and Chiltern White is no exception.