They get snaPped up quickly. Sometimes they'll release more, so keep checking. I booked CLT-LGW because it was cheap (55k miles each with the US MC discount) and 2 weeks later PHL-LHR opened up for th same dates. I cancelled and rebooked so we'd get Envoy Suites. At that time (3 weeks ago or so) tons of availability into both London airports, spotty into CDG and nothing anywhere else. But these awards are a fantastic value and in Hugh demand so they go fast.