When he said London I thought central London, in which case 72quid would be a great rate. I never do comparisons to LNF rates because it's not the norm IMO for folk to look for them (FTers more likely). I do comparisons to prevailing rates. Also, doing comparisons of different timeframes from when a person is actually booking is irrelevant as rates fluctuate. We had an example of someone using points for a $250 stay, thinking it wasn't a good use of points, but the same room the week before was $599. Xmas time at LHR Ren is probably going to be less than in Oct.

To the OP. I'd call Marriott Rewards cust svc & get them to call the property & ask for clarification of the cancel policy & then note your record. Make sure they get the name of the person at the hotel.

Cheers.