Well, after receiving a shit load of spam for a while, and repeated failed attempts to get the site to cron properly (resulting in some tickets taking days to notify me they arrived) I have finally broken down and done the upgrade. This new upgrade also allows CAPTCHA support.

Must admit, it went very smoothly and no problems were encountered. Should anyone need to contact us, you can use http://www.f1-software.com/osticket/ which also has a working 5-min cron job \o/