An additional thing to add... this won't help with your GUF2, but might help you find a use for your BAEC miles...

You can use your miles to make redemption bookings on, among other routes:
AA or LAN to North America (including JFK, MIA, DFW nonstop, LAX, SFO, MEX and certainly others via SCL or LIM), QF nonstop to SYD, LA via SCL to IPC or AKL, IB to MAD, and certainly others I'm not thinking about right now.

Best of all, most of these routes don't involve the fuel surcharge on redemptions that you would need to pay for BA to LHR.

Your GUF2 vouchers may be hard to use unless you find good availability on BA (although a travel agent specialising in BA matters can be invaluable there), but your 500,000 miles should be quite usable on partner flights to any corner of the world.