Zoom and Enhance worked fine thanks ... it's not the easiest thing to view documents but it does work with a little patience
The View Text option works only on the odd PDF... I think if a pdf is created from word etc. the BES is able to look at it and translate the image into text... if the PDF is from a scan of a paper document, it can't read it and stays in image form on the blackberry... it may be just one of those things

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Thanks for your help.