If you're after the Dulux version of Sanderson Snowy Owl, go for Dulux Snow Scene. It comes in at ΔE 2 from the original, which is firmly in "very close" territory — under 2.5, where the difference is so slight most people couldn't pick it out side by side, let alone across a room. With an LRV of 90.3 it's a properly bright, light off-white that'll bounce plenty of light around.
Right on its heels is Dulux Cliff Walk, also at ΔE 2, with an LRV of 88.6. The pair are so close in measured terms that the deciding factor is undertone in your specific light. Snow Scene reads a touch cleaner and brighter; Cliff Walk sits very slightly softer thanks to that marginally lower reflectance. In a north-facing room I'd lean Cliff Walk to take the edge off any chill; in a darker space or for ceilings, Snow Scene's extra brightness earns its keep.
The usual caveat applies, mate: a ΔE figure tells you the colours are a tight match, but it doesn't tell you how they'll behave in *your* room. These very pale off-whites are notorious for shifting with the light and with whatever's reflecting up off floors and furniture. Two near-identical greys can split apart depending on whether you've got warm or cool daylight coming in.
So do the sensible thing before you commit. Get sample pots of both Snow Scene and Cliff Walk, paint two coats onto a bit of lining paper or an offcut of board — not straight onto the wall where the old colour skews it — and move it round the room. Check it morning, midday and under your lamps at night. The one that still looks right at all three is your answer.
For the finish, Dulux Diamond Matt is a hard-wearing, wipeable choice for walls in a busy space, otherwise standard matt emulsion is fine.