For those in the PacNW, you can still shave ~30% off by heading up to YVR and originating there. I’m seeing $890 if originating in SEA, but add in YVR-SEA and the surcharge drops to $605. AA issued BA awards ex-YVR are even cheaper, varying between $320 and $390. Given the club suite on the YVR-LHR and YVR-LGW routes, this is a pretty decent deal (particularly w AA miles).