Hi Pieter,
The cruise ships that use Hull all berth in King George Dock and passengers check in at the P&O terminal building.
It is only the smaller cruise ships that use Hull during the summer for about 3 or 4 weeks usually, consisting of 3 or 4 seven night voyages.
Marco Polo and Azores both used it last year.
Decent photo's can be obtained at the lock gates, which is a public right of way, but it does involve a lengthy walk from the free car park alongside where the POH/POR berth.
Hope this helps.