I've been looking at AMS->LHR->HKG->BKK->SIN->LHR->AMS for next TP year (already). I noticed that if you make the BKK->SIN leg adjacent to the SIN->LHR and leave a couple of days between that and arriving in BKK it knocks about £100 off the price, I was seeing £1328 total for that routing on the matrix.
Despite that not having any KUL in it because SIN is better for TPs, the tentative plan is to allocate a few days out of KUL for some MH tier point runs which can be outstandingly good value, so a separate set of flights to and from KUL and then whatever I can fit in to a couple of days. Another possibility I was toying with was trying some JAL domestics with airport upgrades.