History of Windsor

I was chatting to a local allotment gardener yesterday. He told me that in the 1970s on the allotments betweeen clewer village and windsor rasecourse were a huge quantity of musket balls and clay pipes which seem to have been left by an army encampment. Thehistory of Windsor includes a siege of the castle by royalists during the english civil war and this may account for the camp? If anyone has more info, please let me know.