So pages and groups are meant for advertising aren't they?
Am I missing something? 
Yes you are, I have bolded out the part that I am talking about this is quite new, and I keep a check on facebook pages due to online marketing business I run, Dave I am only trying to help you mate
I have copied a part of facebooks terms for you:
III. Page Features
A. Advertising on Pages
Ads and commercial content (including Page post content) are subject to the Advertising Guidelines.
Third-party advertisements on Pages are prohibited.
B. Cover
All covers are public. This means that anyone who visits your Page will be able to see your cover. Covers can't be deceptive, misleading, or infringe on anyone else's copyright. You may not encourage people to upload your cover to their personal timelines.
Covers may not include:
i. price or purchase information, such as "40% off" or "Download it on socialmusic.com";
ii.
contact information such as a website address, email, mailing address, or information that should go in your Page's "About" section; iii. references to Facebook features or actions, such as "Like" or "Share" or an arrow pointing from the cover photo to any of these features; or
iv. calls to action, such as "Get it now" or "Tell your friends."
I can't use my logo on there as it contains my website address as part of it, a pain but it is free so have to go by the terms they set out