Agree with Vic, engine cover off, remove the fuel rail and the return feed pipes for the injectors - carefully though, lift them vertically with a pair of long nose pliers after removing the retaining clips, then it is just a case of undoing the cover for the crankcase breather - 4 screws/bolts. i changed mine using the bmw part number above, it came with the replacement seals, no idea if it did work though! just take your time and only replace one seal at a time so that you are sure where you are.
in true Haynes style refitting is the reverse of removing!, in my haynes manual it is in but it fails to mention the fuel rail and the return pipes on the injectors...
let us know how you get on.