Following a discussion in the themes forum, I decided to look more into adapting some of the TinyMCE plugins for the new format in 2.4, but I am obviously doing something wrong in the process.
I wanted to add the pwd toolbar toggle plugin (I want to adapt it and take it further, but I want to get the basic one working first) and I started by looking at the Moodle Doc and by using one of the existing Moodle plugins (moodlenolink) as a starting point.
The plugin appears to load ok through the administration/notifications page and my page loads ok. The TinyMCE editor loads up initially with the html content in the editor box for a second or so and normally this would then be swiftly followed by that being replaced by the toolbars and the wysiwyg content of the editor. However, at that point my editor simply goes blank - there is no error message (I have moodle debugging turned on to Developer level) and if I use the chrome tools it shows that the textarea object is still there with visibility hidden, but the wysiwyg editor does not load.
I have no doubt I have missed something, but would appreciate some help and guidance if anyone has the time to take a quick look at what I have done/messed up