Just received another new copy of PDF from same supplier and did as you suggested again, right clicked the PDF attachment on email and saved link to desktop and then went to Adobe reader and did file open and WOW it opened. So lesson is never open this supplier's attachment with out saving link first, then going to Adobe Reader 2nd and opening through Adobe Reader file open.
Hence it is likely to be my system and if I don't follow the process you suggested above all other process's will corrupt file the moment I open it. I will look into resolving this if it ever happens again with any other PDF files sent to me, but as yet it has only been this one provider. A Big thanks for your help, cheers, Annie