LHR-HKG Economy delight £209 for VS Gold?

I've been looking at flights for next year to HKG and might be tempted to go in Economy delight as it's incredibly cheap after rebate. Here's the logic...
The flight is pricing up at £512 for March next year. As VS Gold I should normally earn 28,632 points.
But with the double miles promo for flights booked until the end of the month, I should earn a whopping 57,264 miles! The T&C seem to confirm that the bonus miles are also on the tier bonus.
Now if I spend those 57,000 points in advance as money plus miles I only need to pay £209 cash which is pretty good, I think!
Are there any other sweet-spots for double miles?
The flight is pricing up at £512 for March next year. As VS Gold I should normally earn 28,632 points.
But with the double miles promo for flights booked until the end of the month, I should earn a whopping 57,264 miles! The T&C seem to confirm that the bonus miles are also on the tier bonus.
Now if I spend those 57,000 points in advance as money plus miles I only need to pay £209 cash which is pretty good, I think!
Are there any other sweet-spots for double miles?