Thank you for your quick replies, and I apologise for my delayed response.
Both Andrew's and Graham's codes work perfectly (I added a few lines to Andrew's to convert all caption styles to my default paragraph style as the caption style left too big a space).
You're right Andrew, tables at the start and end of the document were causing the cutting and pasting problem and both your's and Graham's codes deal with it.
I've attached a shortened version of the document (with the text replaced), so you can see the butted tables. At present they're pasting again as butted. I did manage to reproduce the instance of them pasting as unbutted but once again am unsure how i did it. Altering the “Show text boundaries” or setting “Style area in draft and outline views” to a value greater than "0" may have been what was causing the change (from pasting butted or unbutted), but I can't reproduce the effect consistently so I can't say for sure. I'm saying this more for your benefit than mine as it appears to be something some of you are at least a little curious about. I've now got codes that add a space above and below whether they're butted or not so I'm happy enough no matter which way they paste; and the many table and formatting settings (on top of trying to get my head around VBA) is making me tired