Looks like the AARP discount with BA is still working so that could save another $400 off the ticket. A quick google search found
this:
The British Airways and AARP discount, which has proven to be incredibly lucrative for premium cabin travelers, is back at its original level, which means you can score up to $400 off a business or first-class ticket. However, you have to move fast — you must book by June 29, 2017, for outbound travel between August 1, 2017, and January 8, 2018.