Booked UK instead of INT version

Hi, I have booked the UK version instead of INT. I have no need to sit the UK version however it’s too late to change. I know I need to know the differences between the standards, however when I am completing say for example a goodwill question in the UK version, I would use the UK rules? Or do I use the INT rules and be aware of the differences? I am now very worried! Many thanks.