There used to be a frequent MH sale that would have HKG-LHR for around $18k IIRC. Haven't seen this for a while. As it is now, the generally available LHR fare is $23k in D class earning 200 club points. This is more club points than the CX D class fare at 180 points, albeit with a stopover in KUL for the MH fare.
Ive taken that MH flight previously at that price, however I can usually find HKD18k fares to LHR in Qatar sales. I prefer the Doha airport to KUL and the MH planes HKG-KUL aren’t great. Nor is that satellite terminal in HK. However I do love the all you can eat Satay cart!