Huw,
Unfortunately, no, we haven't added the access stuff yet. It is planned for the 5.1 release which may be out later this month or in July. It really hasn't been a highly requested feature, and we always want to prioritized based on requests. We do agree that it's time to get these features into our extensions since we're no longer developing for Joomla 1.5 and, therefore, this should be a core feature of all future releases.
In the meantime, don't worry about the extra uses of our code. While it's not ideal, it's not your problem and it won't affect your subscription. If you want to change your Subscriber ID, you can do so by changing your password on this site. That won't prevent the new ID from being used again though.
Thanks for the report and feedback,
Alex
Component access permissions?
