looks like the same item - preference would have to come down to delivery time and P&P... I do know 7dayshop.com charge £3.95 for the complete order, not per item or set of items.
I've just completed a run of 100 A4 calendars, (including cover page thats 1300 sheets) I ordered 7 of their canon GP501 packs (100 sheets, 170g, £16.99) on a bogof, so got 14 packs of paper .... for £3.95 p&p!
Oh it came in 7 bulky packs as well to avoid vat, had to collect from PO sorting office...