I expected that $/ would be package specific, it doesnt seem to be,
...is there a way to alter the behaviour of $/ to make it package specific?

From perlvar:

Perl identifiers that begin with digits, control characters, or punctuation characters are exempt from the effects of the "package" declaration and are always forced to be in package "main"; they are also exempt from "strict ’vars’" errors. A few other names are also exempt in these ways:

               ENV             STDIN
               INC             STDOUT
               ARGV            STDERR
               ARGVOUT         _
               SIG

In particular, the new special "${^_XYZ}" variables are always taken to be in package "main", regardless of any "package" declarations presently in scope.