I'm thinking the net result is something like this:
WITH SELECTED_DATA AS (

    SELECT C.Cust_MPAN, CONVERT(date, J.PlannedStart, 103) AS [Date], J.[Status], WP.AbortCategory,
        ROW_NUMBER() OVER(PARTITION BY C.Cust_MPAN, J.[Status] ORDER BY CONVERT(date, J.PlannedStart, 103) DESC) AS RN
    FROM dbo.Jobs AS J
        LEFT OUTER JOIN dbo.worksheet_pvt AS WP
            ON J.JobId = WP.jobid
        LEFT OUTER JOIN dbo.Contacts AS C
            ON J.ContactId = C.ContactId
    WHERE J.[Status] = N'completed with issues'
        AND C.Cust_MPAN = N'2199996080116'
)
SELECT *
FROM SELECTED_DATA AS SD
WHERE SD.RN = 1
ORDER BY SD.Cust_MPAN;

Edit: Query corrected to include DESC for the row number order by.