Here's the deets on how to use it (and the all important T&Cs):
"How to use the voucher - open http://www.expansys.com or call the sales line, choose your product(s) and add them to the basket, or tell your sales advisor. If using the web, enter the voucher in the How did you hear about us? space at the check out page, or quote it to your sales advisor.
Terms are as follows: One voucher can be used once for a single order, up to (and including) the 4th of April 2008. Discount will be applied to the cost of goods only and excludes delivery charges. Not to be used in conjunction with any other eXpansys offer. Your £10 discount will not show in the check out process, but will be applied when the order is processed. If you use the voucher on another international eXpansys site (see www.expansys.com/group) then the discount will be re-calculated to that websites closest currency equivalent. See http://www.expansys.com for full terms and conditions."
Not bad i'm sure you'll agree note also that it should be valid on all worldwide eXpansys sites!