If you want the Dulux stand-in for Wimborne White, go with Dulux Jasmine White. It lands at a ΔE of 0.9 from the original — that's below the threshold where the human eye can spot a difference, so in practice you're looking at the same colour. LRV 86, which keeps it firmly in the soft, light, warm-white bracket Wimborne lives in.
Close behind is Dulux Fine Cream at ΔE 1.1, LRV 88.8. Still a cracking match, just a touch lighter and brighter. If your room is on the gloomy side and you want to squeeze a bit more bounce out of the walls, Fine Cream is the one. If you want to nail the F&B reference as exactly as possible, Jasmine White wins.
Why bother matching at all? Wimborne White is one of F&B's warmer, creamier whites — it's got a yellow undertone that stops it going clinical, which is exactly why people love it on woodwork and in north-light rooms. Getting that warmth right is the whole game. A generic brilliant white off the shelf will look stark and cold next to it, so don't be tempted to just grab any white in a hurry.
The usual "but what about" here: matched colour doesn't mean matched finish. F&B's Estate Emulsion has a particular chalky, low-sheen flatness that Dulux emulsions won't quite replicate. The hue will match to within a hair, but if you're patching into existing Wimborne White, the sheen difference may show in raking light. For a fresh job across a whole room or all the trim, you'll never know the difference.
Practical tip: buy a tester of Jasmine White and brush it out next to your Wimborne reference on a bit of lining paper, then view it morning and evening. With matches this tight you're really just confirming the finish and sheen suit you — the colour's already sorted.