Thanks for all the replies, turns out the problem was my 32bit ODBC driver wasn't happy with Activestate's 64bit Perl, I couldn't find a work around so removed Activestate and replaced it with Strawberry Perl 32bit and I can now connect successfully.

I used to spend a lot of time on this site but can no longer access my account (long forgotten/lost email address).

I still write a lot of Perl, along with Golang and NodeJS but it's good to be back even as an anonymous monk.

Thanks again.