Feltwell said:Errrmmm - they look a little like bullets to me, do be careful....
You can't tell without measuring them, so I'm prepared to be totally wrong, but they look like early 1900s military ammunition. Someone seems to have used your hill as a bullet stop. The most numerous ones may be early .303 rifle bullets; the later ones, from the Mk7 on had a more pointed nose.There's an article on .303 ammunition on Wikipedia. You may be able to tell where the firing point was and then find some matching cartridge cases.
The lead bullet below the egg may be a .455 revolver (Officers, for the use of). The rimmed brass cartridge case below that will have numbers on its base that will identify it. It looks like a revolver cartridge, but might be a broken .303 rifle cartridge.
They all look like fired small-arms ammunition and so shouldn't be dangerous. If you find any old live rounds, I think they can be hazardous; the propellant contained about 10% nitroglycerine (I think) which can separate and is sensitive to shock. I've never heard of one going off.