1) I travel to London on business 2-3 times per year.
2) I prefer the Dorchester over The Royal Garden.
3) However, like the others, I think cash is better than points.
4) If you decide on cash, then you have a lot of choices.
5) There are five-six great hotels nearby.
6) If possible, pick one on or just off of Park Lane
. . . mega-shopping on Oxford is very close and walkable
. . . buses go to Piccadilly or Harrods with one or no changing
. . . easy cab or bus access to the West End theaters
. . . subway ("tube") access nearby
. . . across the street is Hyde Park