I use a spreadsheet when ordering from UK DS, attaching it to an email. I use three columns, part number, description and quantity. (Actually, I use more than three columns, but hide the others when I send the order in as they are only of interest to me.) With my last order, I asked if they preferred the order sorted in ascending numerical order of part number or random and whether they wanted the column in with the part description in. The answer to both questions was "Yes" as structuring the spreadsheet this way helps with its processing.
BTW, when ordering by email I have found on a number of occasions (and I think Martin has too) that using the generic email address is unreliable so I always use a specific staff member's email address.