My dad went off and bought a standard Halfords trolley jack - smaller than our usual main jack so we could get under the sills easier - but the end fitting wasn't particularly secure in the BMW's designed jacking points.
All credit to Dad here, he machined some custom adaptors to suit the 3 series jacking points, and to replicate the shape of the standard end fitting into the jack.
Here is what he came up with, pretty decent bit of kit.
