Funnily enough a friend asked me a near identical question yesterday. The best value I could find for her particular dates to KUL was with Qatar from Paris, which cost a few hundred pounds more than economy from London (and some business fares were cheaper). Qatar is in the same alliance with BA and so you can spend and redeem on them, as you can on MAS.

Using Avios for economy on that route with that timeframe is unlikely to be good value, unless you have acquired a big stack for no money! It's best used for almost anything else frankly.

But welcome to Flyertalk u89cs, it's good to see you here on the BA Board, and I hope you will continue to play an active part in this forum. Welcome on board.