Hi Stuart - I must have missed these replies, apologies. Sadly the Dutch tweeter doesn't know where it is - someone else asked the same question. I imagine that the IWM will hold a much higher resolution print than the one online, as they certainly do for other images. But it'll cost to obtain it...
As you say, the photographer was Hampton - it lists him a bit further down the page (he's a photographer I'm quite familiar with as I've been using his photographs from Normandy for landing craft research). I've seen a few original copies of RN and AFPU prints and sometimes the photographer's name is used as a catalogue/reference number so it could be that.
Bear in mind that an awful lot of images from the IWM collection aren't digitised. However, just searching the series that the picture is a part of reveals this one as well: https://www.iwm.org.uk/collections/item ... /205158127