Not massively expensive but I think that these are ground dug rather than found on U534. If you look closely you can see roots of vegetation. Nothing would have grown in a dark uboat. Some of the other stuff looks nice and clean nice shiny plug on one item (probably from an aircraft?). There is also a car battery cap by Varta on one grouping. This ground dug"uboat" stuff is quite common by the looks of it.

Group of electrical parts which are bakerite parts and bulb nice clean parts recovered from U-Boat U534 which was sunk on the 5th May 1945 by RAF Bombers | Relics from the Front