Before you continue you may wish to consider the data types you have and what you are trying to achieve, The following may help in the right direction:

SELECT M1, M2, CAST(M2 + ' 01 ' + CAST(LEFT(M1, 4) as char(4)) as date) MonthStart,
DATEPART(QUARTER, DATEADD(MONTH, -3, CAST(M2 + ' 01 ' + CAST(LEFT(M1, 4) as char(4)) as date))) FinQtr,
CASE
WHEN DATEPART(mm, CAST(M2 + ' 01 ' + CAST(LEFT(M1, 4) as char(4)) as date)) < 4 THEN DATEPART(YEAR, CAST(M2 + ' 01 ' + CAST(LEFT(M1, 4) as char(4)) as date))
ELSE DATEPART(YEAR, CAST(M2 + ' 01 ' + CAST(RIGHT(M1, 4) as char(4)) as date))
END FinYear
FROM TEST
ORDER BY FinYear