any quick pointers to how/where to make the settings to save me any time looking?

If setting it on the hub, it might not be available. Usually only the expensive "managed" hubs have web or software interfaces for configuration. If this is available, it will be in the manual for the hub.

If setting the speed of the ethernet card on the PC, it depends on the card. Some drivers will have this option available in the Network control panel somewhere. Others (like a 3com card I just worked on yesterday) require booting to DOS and running a utility off of a floppy disk and setting the option in the utility's text-mode screen.