Lookup formula that returns unique multiple search results WITH ATTACHMENT

Hi.

I have two columns of data - first shows sales order numbers and the other a list of product codes. I am attempting to lookup and display on a row horizontaly the multiple entries that exist in column 2 against column 1.

I have an array formula that transposes the entries in coulmn 2 in my summary sheet:

IFERROR(INDEX(Orders!$H:$H,SMALL(IF($A$7=Orders!$D:$D,ROW(Orders!$D:$D)-MIN(ROW(Orders!$D:$D))+1,""),COLUMN(A1))),"")

However, the problem is that coulmn 2 contains duplicated entries and I only want the unique entries; i.e, in my summary sheet, alongside my sales order number, in the first available column, bring back the first unique product code, then in the next column bring back the next unique entry, and so on....

Thanks.