Can't delete a filespace

I’m baffled by this one but I suspect I’m just missing something obvious.

We have a server named ESTREAMC. I am trying to delete one of the filespaces associated with this server via the CLI but I can’t get it to work.

I issue the command:

q fi ESTREAMC

and, sure enough, among others, the F: drive/filespace appears:

ESTREAMC \\estreamc\f$ WinNT NTFS (etc).

but when I try to delete it:

del fi ESTREAMC \\estreamc\f$ TYPE=ANY

I get the following error message:

ANR0852E DELETE FILESPACE: No matching file spaces found for node ESTREAMC.
ANS8001I Return code 11.

Any suggestions please?