How do I mark 2nd entry duplicated

HI

On sheet 2 I have a worksheet that shows OK in column E if there is a matching entry on sheets 1 or 3. Issue I have is there are sometimes duplicated entries on sheet 2 and they are not marked.

What I'm trying to do is if there is an entry on sheet 2 and it has OK marked in column E of the row I need it to check the rest of the data in rows that don't have anything in column E.
When I mean check data look down every row and see if data matches across the row in columns A-D as stated don't have anything in column E I need that one marked "DUPLICATE"

Any ideas?

If you look in the tab called WATFORD you see there are 2 entries for

1371 229 04/03/2025 24.00

One of them is correct as the data is in the tab called tableau but the 2nd is a duplicate entry. Thats what I need marked as DUPLICATE. Issue is they will be different entries and will be all over the workbook in any row down the workbook.

What im trying to do is where there is no entry in column E of workbook called WATFORD I need it to look down the worksheet and if there is a exact match across columns A-D and nothing in column E I need that column marked DUPLICATE.

Hope that makes sense