Sorting by Month as Text (Jan Feb Mar etc)

OK got it

https://support.powerbi.com/knowledgebase/articles/592116

Go to data (left hand side button) and click

Then go to the table to be sorted (right hand side)

You will need three columns in this calendar table for month

create

1  Main column (to set up the link column for Invoice Date) 

   CalendarInv = CALENDAR (MINX(Header, Header[Invoice Date]), today())

2  Column for month in text format

    MonthT = FORMAT( CalendarInv[Date], "MMM")

3  Column for month in number format

    MonthN = Month (CalendarInv[Date])

Then go to field list on the right hand side Click on MonthT

then go to modelling / sort by column and select MonthN

 The final step is as follows

NB Creating calendar table

http://community.powerbi.com/t5/Desktop/Possible-Tip-Trick-Dynamic-Date-Dimension-Table/td-p/8462