I'd very much appreciate any information about these pieces. I have always taken it that they were drill rounds. They have no markings of any kind that I could see and I rather lazily assumed that they were for the 40mm Bofors. However I notice that they are not 'necked' in any way unlike other Bofors rounds, which has led me to wonder. They are just over 400mm tall, about 55mm across the base and appear to be solid brass with a steel base. It has been suggested that they are from a 2pdr Anti-Tank gun and looking at other examples of live ammunition for that gun there is definitely a resemblance, but I can't find a comparable example to these as a drill round, as the others seem to be wooden with brass nose and base.