I downloaded the package, read the manual page, and saw the manual page uses:

use  Geography::NationalGrid;
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So, I tried:

$ perl -MGeography::NationalGrid::IE -we1
Can't locate object method "deg2rad" via package "Geography::NationalG
+rid" at /opt/perl/lib/site_perl/5.12.2/Geography/NationalGrid/IE.pm l
+ine 7.
BEGIN failed--compilation aborted at /opt/perl/lib/site_perl/5.12.2/Ge
+ography/NationalGrid/IE.pm line 7.
Compilation failed in require.
BEGIN failed--compilation aborted.
$
$ perl -MGeography::NationalGrid -we1
$
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