I did get, from the cpan documentation, that the result from the $cvs->status command was an object, but the returned object was of type Cvs::Result::Base which does not have the method status.

However using Dumper (good advice, thanks) I noticed that the 'pwd' field in the cvs object was not pointing to where the checked out view was, so I changed the code from

my $cvs = Cvs->new('workdir' => '/projects/millerb/SR/vhdl'
                   ,'cvsroot'=>':pserver:millerb@172.20.175.10:/hwcvs'
                   ,'password' => '********'
                   ) or die $Cvs::ERROR;

TO

my $cvs = Cvs->new('/projects/millerb/SR/vhdl'
                   ,'cvsroot'=>':pserver:millerb@172.20.175.10:/hwcvs'
                   ) or die $Cvs::ERROR;
[download]

Which seems to have resolved the issue. Thanks Brian