BMW Questions? Ask a BMW Repair Expert for Answers.
did you remove 15 bolts or what exactly did you remove?
another expert here
I'd say that you need a single point ( 1 hex) 1/4" drive deep socket as these tend to have the thinnest walls and as the torque is pretty low on these fasteners then you can also turn the outside of the socket down if required
A lot of BMW tools are pretty skinny so I'd not worry about keeping the socket perfectly square and true and I'd ground down plenty of sockets by hand with a bench grinder
or even use a belt sander with a long m6 bolt through the middle of the socket so it can spin and you've something to hold it with
as for if its a 10mm or not then I'm about 90% sure it is a 10mm but some locations do also use a 8mm