Many thanks for your reply. To give you a brief background, we updated our website from Frontpage to WordPress, and used a 3rd Party to create it for us. Whenever they handed over control, they gave us the 2 accounts and said that we would have no issues.
Heads of Dept will only ever be updating their own subject page, so you wouldn't have the like of a P.E teacher editing a Physics page at the same time as a Physics teacher... or at least I would like to think not! lol
My initial query has come about as a "possible" problem we had earlier in the week.
We held staff training for guidance on how to update the website. A number of the staff had a problem in that the "Editor Toolbox" didn't appear for them. I'm not sure if that's the correct name for it, but it's the box of options like Bold, Italics, Alignment, Links, etc. that normally sits on top of the content box.
I'm not sure whether having multiple people using the same login details would be to blame for this, or I should be looking at some other possible solution.