Hope this helps!

It helped immensely thank you...
It forced me to go and find where I had got push_header() from. In doing that search of source code it twigged that it was not the header that needed token_type but the content. With that realisation, the rest sort of fell into place.

Here is the working overridden sub in case anyone has a similar problem and comes across this in future:

sub construct_tokens {
    my ($self, $oauth2, $response) = @_;
    
    my $content = eval {decode_json($response->content)};
    unless ($@) {
        $content->{'token_type'} = 'bearer';
        $response->content(encode_json($content));
    }
    
    $self->SUPER::construct_tokens($oauth2, $response);
}
[download]

Can anyone explain what the documentation means when is says to contribute one should submit a git pull request? I would like to contribute my LinkedIn solution when it is complete and tested as I am sure I am not the only person wanting to connect to LinkedIn with Perl.