Coupon text

I wrote a tutorial on this over at Sell With WP, How to Rename or Hide Coupon Code fields with WooCommerce ??

Max – I have a similar yet I think simpler problem.

I just want to change the message/’text’ in Checkout : from ‘have a coupon’ to ‘insert discount code?’ I don want to hide, just want to use the word discount, not ‘coupon’ (not a word universally used in the UK – we like ‘discount’)

Can you point me to where I can change tis text please?