Thank you for responding. I confess I am an utter novice at php. The code is the sample code provided by linkshare so I assumed it must be correct

I will keep your response in mind and relook the code on these lines.
Having said that, I believe your final comment with the php page is perhaps what I have been trying to find - the key to linking the form to the action. I am most grateful, thank you. I will certainly advise you if this has worked for me.