The lines that belong together
Order M-envelopes on their own line.
They still post as a parcel format. Check the format before you assume a letter.
The line that stays separate
book wraps stays on its own order line. Using a book wrap because the M-envelope size is out changes the pack.
M-envelope boxes is the range Packaging Boxes uses for M-envelope boxes.
One basket
They are a different range from book wraps, which are E-flute with a peel-and-seal strip.
A Friday order on Packaging Boxes that includes M-envelope boxes aims for Monday. A bank holiday on Friday or Monday moves that delivery. The 3pm cutoff is still the same-day dispatch rule.
Open M-envelope boxes when you already know this line. The page shows the pack quantity. Packaging Boxes will still dispatch an order placed by 3pm on the same day.