Dammit! looks like i must have a rogue module somewhere then. I've just done the following:

sudo perl -MCPAN -e 'install Net::SFTP::Foreign'
[sudo] password for purcedw1:
Reading '/root/.cpan/Metadata'
  Database was generated on Wed, 02 May 2012 04:58:03 GMT
Fetching with LWP:
ftp://ftp.mirror.anlx.net/CPAN/authors/01mailrc.txt.gz
Reading '/root/.cpan/sources/authors/01mailrc.txt.gz'
......................................................................
+......DONE
Fetching with LWP:
ftp://ftp.mirror.anlx.net/CPAN/modules/02packages.details.txt.gz
Reading '/root/.cpan/sources/modules/02packages.details.txt.gz'
  Database was generated on Thu, 03 May 2012 11:15:03 GMT
......................................................................
+......DONE
Fetching with LWP:
ftp://ftp.mirror.anlx.net/CPAN/modules/03modlist.data.gz
Reading '/root/.cpan/sources/modules/03modlist.data.gz'
......................................................................
+......DONE
Writing /root/.cpan/Metadata
Net::SFTP::Foreign is up to date (1.71).
[download]

Thanks for the prompt reply - i shall confirm in due course :)