Like Tim, I am still waiting for wills ordered on 25th July, 3 of them in my case. I received one I ordered that day just 2 days later on 27th July, but that was a soldier's will (from WW1) so that was presumably treated differently. The 3 wills I am waiting for are for deaths in 1903, 1928 and 1958.
As Tim suggests, maybe the newer the will, the quicker the delivery. I notice there are separate tabs for 1996-present, 1958-1996 and Soldiers' wills. That maybe indicates there are 3 different streams, taking very different times for delivery.
I wonder how many of the wills people received quickly are in the post-1996 or soldier's wills categories?