"Robert11" asked:
... does anyone know of a source (assuming they exist) for a
BNC to BNC that swivels between them ?

I've used a pair of right-angle BNC adapters to provide a universal
joint. The arrangement allowed the antenna to sit along the side of the
scanner while clipped to a belt, without poking me in the ribs.
And, yes, it also provided an attenuator in the process.