Brilliant, thank you for the quick reply!
I was worried it was on the inside but in that case I will get it sorted asap.
When you do it get some masking tape to go all the way around your headlights to protect the surrounding paint work from the sanding pads and mop with PlastX. Also make sure you follow the instructions about using the sanding pads to the letter and use them in the correct order.
e.g. Roughest grade>smoothest grade.
If you can as well buy some UV protection to go on top of the headlights afterwards to keep it from getting UV damaged again for as long as possible.