Toby - You might want to consider a lifeline: use a tapestry needle to run a piece of different colored waste yarn or crochet thread through the stitches on your needle/cable before proceeding to the next row, making sure the row you're using is correct first. Then if you have to rip back your stitches are secure on that waste yarn/thread, just place them back on your needle and start again.
Re your pattern problem - I agree with Jan. The (p1,k5) is done twice on every repeat, using up 16 stitches each repeat (k4 + p1,k5,p1,k5), so you do it 5 times (first time around then 4 more times as stated), for a total of 80 stitches. the k6 at beginning and end of row is another 12 for a grand total of 92 stitches, which is what I believe you started with?