Thank you for the quick response Kyle.
The code works perfectly - sort of! The counters are working but not displaying because the <div> is within the <textarea> tags. Like so:
<textarea>"text here"<div id="remainingCharacters">927</div></textarea>
I've tried playing around with the code for ages but can't for the life of me figure out how to make the <div> appear outside of the <textarea> using this code as a basis.
Help very much appreciated.