Hello, I got it done by my local mechanic (in London). Gave him all the videos and manuals I found online, and spoke to the head of workshop at a BMW garage before doing it. BMW said "none of our technicians touch an i-car unless they've been high-voltage trained" (implying that I'd kill myself) but in reality, just avoid the BRIGHT ORANGE CABLES! It's just a 2-cyl 660 cc scooter engine under a cover ffs! Undo the 8 torx screws on the composite engine cover under the boot floor, the oil filler neck is clearly visible. Warm up rex, put on ramp and drain as usual.Takes about 20 mins. Cost me £160 instead of £560 (ok, without £150 of BMW "inspection") including BMW parts and £60 of labour. The car is pretty sophisticated at self-reporting any faults, and you can check bushes, shocks, brake pads and discs, tyres and lights yourself.