There's a proper close match here, so you can save your money without compromising on the colour.
The two to look at are Dulux Jewelled Creek 2 (LRV 21.5, ΔE 1.9 from the original) and Crown Button Box (LRV 20.1, ΔE 1.9). Both sit under ΔE 2.5, which means the difference from Burlington Arcade is very close — the sort of thing you'd struggle to pick out on a wall, especially once it's dry and viewed in normal room light. Either is a genuine dupe, not a vague approximation.
COAT Mr. Clifton (LRV 23.5) comes up too, but at ΔE 4.2 it's a noticeably different colour — a touch lighter and off in tone. I wouldn't reach for it if matching Burlington Arcade is the goal. It's a lovely shade in its own right, just not this one.
Between the two strong matches, your choice comes down to finish and where you're buying. Dulux is everywhere — trade centre, decorator's merchant, sorted in five minutes. Crown's match is just as tight, so if your supplier carries Crown, Button Box is every bit as good a bet.
Now the honest bit: what you're paying extra for with Mylands is the depth of the finish. Their paint is richly pigmented and the film has a beautiful quality to it, particularly in the sheen finishes. On a feature wall, a chimney breast, or a panelled room where the paint is the star, that's worth the premium. On a hallway, a rental, or a big surface area where you just want the colour right, the Dulux or Crown match will look cracking and leave you with cash in your pocket.
My advice: buy a tester of whichever match you choose, paint a decent patch — A4 at least — and live with it across a day. ΔE 1.9 is reassuringly close, but seeing it in your own light is what settles it.