There are some BMW offers with dealer deposit contributions available which go alongside the complimentary upgrades. There is a lot of 'smoke and mirrors' with this though. A 10% discount is probably not that easy to come by, unless the dealer group is big (Sytner etc) and it is the right time in the trading cycle (near the end of the quarter) to force their hand. My local dealer is just a singleton family run business, they could only offer 6% off list, presumably becuase they do not get the volume of business to qualify for the volume bonuses from BMW UK.
If you are in the police force/military you can get exceptionally good deals - discount and v cheap finance rates.