When Freeth meets Gibson under the canal bridge, a barge is trundling past. When the camera cuts to Carter watching them, there is no barge in sight, nor are there even any bow waves from it.
When Freeth barges into the door to enable entry to the flat, it already appears to have started to dislodge itself from the frame a second or two before impact. Further, no splintering sound can be heard, nor are either the door or the hinge mortises on the frame damaged.
When Regan asked Freeth (James Cosmo) what a 'Teuchter' was (Freeth was on tape calling Regan a Teuchter), Freeth said it was a Highlander's word for a punter. In fact, a Teuchter is a Lowland Scots word used to describe a Highlander, in particular a Gaelic-speaking Highlander.