@DFink I’ve managed to find a previous post with a solution for text mirroring (Mirror input field to a text field on keyboard strokes - #2 by Noah-R), however, I now need to add a custom formula to add to the text output to display a price rather than just mirror.
<script>
var inputBox = document.getElementById('orderValue');
inputBox.onkeyup = function(){
document.getElementById('deliveryPrice').innerHTML = inputBox.value;
}
</script>
Next problem after that would be to format the input as a financial value i.e. currency symbol “£”, decimals and 000,000 comma separators.