i bought something online and its coming by royal mail special delivery, i emailed the shop earlier to ask when it would arrive so i could make sure im in and i was told that it would either be with me today or monday 
im a bit confused as we get post here on saturdays too, does special delivery only cover monday to friday? i had a look on the rm website and it said
"If you need your item sent over the weekend, you can also arrange a guaranteed Saturday Delivery available at just £2.25 extra per item"
does this mean it can also arrive on saturday without paying the extra?

im a bit confused as we get post here on saturdays too, does special delivery only cover monday to friday? i had a look on the rm website and it said
"If you need your item sent over the weekend, you can also arrange a guaranteed Saturday Delivery available at just £2.25 extra per item"
does this mean it can also arrive on saturday without paying the extra?