> > Clues greatly appreciated?  If it matters this is a /arm32 machine running
> > -current that is probably a couple of months old by now.
>
> You do have 'file-system UNION' in your kernel config right?

D'Oh!  Its in all my kernels except the one I happened to be
running at the time!!

Many thanks for solving that one...now for the next question


Q: Is it theoretically possible to have an NFS mounted upper layer?


Thanks,

David.