as far as aware engine ought to be level ( airbox) but have noted as you comment that almost all ( including mine) are sloping to left ( viewed with bonnet up from radiator) .
There should be two square plates under the nuts and washers that hold the mounting to the base unit, and those plates ensure that the engine is sitting in the correct position.
The plates are part no 572869 below:
The V8 engine / Cylinder Block 2.jpg
do you have a link to the rear engine mount for BW65.
Don´t forget to change the rubbers from the engine steady bar. My engine mounts look ok, but the steady bars are in very bad condition. Will change both, got everything from Geoff. For steady bar he offers standard rubber and PU.
As typical German I ordered the cheaper ones.
With headers off and radiator out access is fine