No interactions present.
Tim, you're right. In fact, there is a very easy character to tell the difference. All the pods are much longer than their stalks.
Not sure that always holds true though - when I did the measurements for my crucifer handbook there were certainly some tenuifolia fruits longer than their pedicels
Another character hits the dust. I read this in Clapham, Tutin and Warburg, which is usually a good source of character descriptions.
Lat/Lng: 53.4762, -3.0322
OS grid ref: SJ315982
suburban garden but within 500m of dunes and beach