The confirmed pence list is a great piece of work, I had assumed that common titles like FF or Spider-man had pence copies of all distributed issues. No work for me today so just spent morning comparing pence list to my comics and they match almost exactly, as I collected most of my silver age collection in UK pre-internet I have a lot of pence issues but my pence/cents list mirrors Marwood's. I noticed a number of issues you list as no pence copies Duncan McAlpine's guides show as scarce or uncommon in UK, my copies of several of these are unstamped cents copies making me wonder whether there are more UK non-distributed issues than previous guides have suggested. I could only find one pence issue in my collection your list isn't showing, I can't believe its not common in UK so probably glitch in your list. (What a bargain, Barry Windsor-Smith double sized issue for 6p!)