Thanks Jason I will try this late tonight when most of the population are asleep in case the page goes wrong..as uploading it on the live server.
once this is sorted, I wanted to make sure that if a customer had used a voucher code that made the transaction go into a negative value, I would then use a IF statement around the total price, grand total price etc to check if <0 then display 0 so that the customer will never see a £-5, £-10, £-15 etc etc. however this would mean I would need to make sure i do that for every instance in my website...if there some kind of "global" IF statement I could do as a function so that any values in my website with a negative value are displayed as £0
Chris