Show minor unit labels for chart

[Back2Basics]

I have a chart and i wish to show the minor and major unit labels, however I can only seem to show the minor unit gridlines. I do not wish to show the gridlines for the minor unit only the major unit.

I'm not quite sure how to get around this.

I have posted a spreadsheet so that you can see what I have already.
As you can see i have months every year, but I want to have labels for every 2 months.

TIA