Originally Posted by
andrewjsl
Thanks for your help. I don't have status with Aeroplan, so I guess I won't be able to upgrade after all

Oh well.
All hope is not lost! Just call up AC and pay up to executive class ;-p
Seriously though, there aren't really too many shortcuts. You need to give AC a bunch of money before they start giving you freebie upgrades. Make sure you have your AP number on the LHR trip's PNR, you'll be on your way to some status!