Thanks Suzeeq, but I tried that and if you are binding off at the end of the row, your yarn ends up still at the end of that whole row. Do you know what I mean? Unless I purl that whole row and then turn around and bind off the three stitches at the start of the next row, which doesn't seem to be what the pattern is telling me.
(As an aside, there is very little in the way of method written on this old pattern. Tells me to do the ribbing for 9 rows then just simply states that I should follow the pattern above)