Hello Adrian,
My name is Gilad, and I specialize in creating custom-made, interactive PDF forms, including all the scripts required to make them work as they should. I had a look at the file you shared and this should not be a problem. I'm available to start working on it right away.
A little bit about me: I'm an Expert on both the Adobe and AcrobatAnswers forums and have a website dedicated to my custom-made tools for PDF files that you're welcome to check out (Google my handle-name to find it).
You're also welcome to check out my work history on this site and see some of the PDF-related projects I've worked on in the past.
Regards, Gilad (try67)