Thanks (yet again) to Mike Gunderloy I've come across Unfuddle, who offer online source control (via Subversion), bug tracking, etc.

Unfuddle is a secure, hosted software development environment and project management solution for small software development teams.

We know that you don't have time to get a server up and running and then configure and secure code repositories, ticketing systems and project management tools.

Their plans start from free (which obviously appealed to me), and their customer service has been excellent, being very responsive to my somewhat cheeky request to load an existing SVN dump file even though as a self-confessed cheapskate I'm of course using the free "private" plan.

Highly recommended...