Thanks, yes it seems that creating a new settings.json file in the .vscode directory at the root of the project allows me to setup project specific settings. From there I could set the path to the perlcritic binary passing in the profile as you suggested.

{
    "perl-toolbox.lint.exec": "/usr/local/bin/perlcritic -profile '/Us
+ers/geraint/Projects/thisproject/.perlcriticrc'"
}
[download]

Thanks for your help!