Well spotted. I hadn't thought of that.
So in answer to the OP's original question, there's just little or no availability?
The extra
Y Award Availability in your screenshot is for Elite BAEC members only (according to your profile you are BAEC Gold).
Otherwise, there is no Award Availability (this can be confirmed more explicitly via the
[Awards/JL-OneWorld] Method):
[KVS Availability Tool 7.0.3/Diamond - Axess: Awards/JL-OneWorld]
Code:
SEA Seattle Metro / Seattle/Tacoma Intl WA US = SEA BFI [KSEA]
LHR London Heathrow UK [EGLL]
MON 01 Jul 2013
Carrier Flight From Depart To Arrive A/C St Availability
--------- ------ ---- -------- ---- -------- --- -- ------------------
BA 48 SEA 18:45 LHR 11:50 +1 744 0 FS0 CS0 WS0 YS0