Thanks calguy1000. As a study of these forums reveals, you are a principle and well respected contributer. So I suspect that I may be suffering concept failure. Let be address your points from my point of view and then you can tell me where I've got it wrong.
1. I suggest you read the default content pages that come with CMSMS. They explain a great deal of how CMSMS works with pages and content and styles.
Yep, I've done that twice now and can only find a couple of references to using style sheets. In particular it appears they can only be included via
{cms_stylesheet} in the template.
2. styles should NEVER be embedded into content areas. You need to understand the concept of separation of design and content.
Yes I understand that concept well, and generally adhere to it (though I note that the minimal template included with the default content, doesn't adhere to that rule). In our case we have the main style sheet embedded in our Smarty header template (as per concept), but one page requires quite a bit of additional CSS. It would be inefficient to include this in the main CSS, just for the sake of one page. So we include that in the header template using a bit of Smarty code that detects the page that the header is part of.
Now, using
{cms_stylesheet} how can I conditionally include that style sheet for this one-off page? I couldn't see a way so tried to include it as chunk of style at the head of the content. This appears to be me, to be a no-no with CMSms, I hope I'm wrong.
3. WYSIWYG editors are not text editors. They will strip out tags they don't understand, and TinyMCE and MicroTiny (both based on tinymce) will both do this.
That seems entirely reasonable under the circumstances, though I did rather expect that it would have shown up with HTML turned on, but alas no.
Thanks once again for your speedy response.
Oswy