I think as you look at the engine from the passenger side the oil temp and oil pressure senders are at the front below the oil filter housing, just behind the power steering fluid reservoir (I think that's what it is - the black thing ringed in my photo). You have to unbolt the power steering reservoir first and pull it out of the way.
Then you can see the senders, one has a single cable, the other has two. I believe they are the two we need to replace.
For the water temp, DNA recommended leaving the original sender alone, and putting the new sender into the engine block. Apparently at the driver's side, under the exhaust manifold there's a redundant plug that can be unscrewed, into which you screw the new ETB sender unit. You have to access this from under the car, and if you are really quick you can remove the plug and screw in the sender without losing much coolant. I expect you'll get that awful cold water down your sleeve feeling though......
I have not done mine yet, but have checked to find the locations. I don't have a deep enough socket to remove the BMW sender units at the moment.
Update. I did my water sender yesterday. Easy as pie.
Jez