BTW I have Adobe Acrobat 8 Pro ... is this the problem (I cannot justify spending on an upgrade) ?
I think the crucial point to understand is that PDFs are really not made for editing, and editing is a desperate last resort. Later versions of Acrobat change stuff, but I doubt much would help. For instance, the 2015 and the shadow behind it were one thing in the design app but are two entirely unconnected things in the PDF.
I observe this was created in Illustrator CS4. It might be editable in Illustrator CS4 or later if the creator was kind enough to set a special flag when saving the file - but as that doubles the file size they probably turned it off.
The client needs to either provide you with an original editable file, or pay you to redesign it completely in a suitable DTP app. And - taking a tangent which I hope is interesting - a slight warning buzzer sounds here: the client almost certainly paid some other designer to make the original, and there is every chance that designer still owns all the rights. Sometimes a client seeks to get work adapted more cheaply without considering whether they purchased the rights to do that. Just tread carefully (and consider how you'd feel and what you'd do if the situation was reversed).
Thanks for that and the advice ... yes I've now opened it in Illustrator but each line of type is a different layer - I think I'll need to dig a little deeper (I don't know illustrator either - I'm a photographer/motion graphics designer so really only use Photoshop and After Effects ... the client created this document himself but doesn't have time to change the dates and the images for the new year so I'm not treading on another designer's territory. I'm kind of doing him a favour (he gives me a lot of photography work).
Thanks for taking the time.