I had a good experience with BCA once with a key. The auction catalog said that were two keys with a BMW 1 series. (obviously the expensive wedge keys) so this was a bonus for me as it wasn't a cost I had to factor in. When the car was delivered, low and behold, only 1 key.
I contacted BCA at the earliest opportunity and they were more than happy to reimburse me cost of a replacement key.
Good Luck, James