Solving Sudoku puzzles made easy (part 6)

We're doing column six, which has 2 and 6 missing. The 6 can't be in the middle-bottom box, so put it in the centre box and do the 2 in the middle-bottom box. (I could have done this before the previous step, same difference).
Then do row five, we have 5 and 8 missing, so write them down in the margin.
There's already a 5 in column seven, so put the 8 in the middle-right box and then do the 5.
That leaves you with only one place in the centre box where the 8 can go.
Then note where the 1 and 4 could go in the centre box.
Next, we'll attack row seven, so write down 1,2,4,5 in the margin.
To tidy up row one, write in where the 6,7 and 9 could go in the top-right box.

Full series here.