Layer de-lamination problem with bowden style extruder

Had the Sunhokey Prusa i3 printing fantastically but ended up getting the PTFE tube clogged (due to old filament I assume). After unclogging the tube and putting the extruder back into place I can't seem to get a good print. First layer seems to go down fine but now of the layers seem to be sticking together. I have a Bowden style extruder and I'm wondering whether maybe I have not put the hotend back together properly.
Here is an image of the most recent failed print: http://imgur.com/a/7Hvjq
Any clues?