Hello,
I would like to be able to have a button that scans all used tags in a folder and then creates a simple list of these tags to aid with consistency of tagging.
I am not sure where to start. Any help much appreciated. 
You could do that using a fairly simple script that loops through the files, builds a list of tags, and then displays them in a message box or even a custom dialog box.
If the files aren't using more than one tab per file then you could also group by the tags column to get a quick overview of which tags are being used, since each tag will create a separate group.
Thanks Leo
...when you say simple, how simple? 
I have made the "hello world" script!
Should be simple if you know a little scripting.
The default script you get when you create a new button and put it into script mode will show how to loop through the selected files.
The example code here should help with the tags:
We can help with anything else if you get stuck.
You might like this script: