Dirk, I have information about battlefields excavations about WWI because it is so close in our neighbourhood. Regularly a farmer ploughing his land "meeting" an obus that explodes damaging his tractor and many times himself too. As I read recently.... Up to my knowledge we haven't had yet deads until now...
As about Waterloo I guess, the deep "scars?" (littekens) in the ground are rare? And as such most was in the upperground and I suppose as there was so much battlefield thiefs afterwards that even a fork would haven't been found anymore after sometime...and in that time the common man hadn't that much as now, I guess...
Even some week ago as someone had discovered an obus of WWI...the demining was alerted, but when they came at the place the obus was stolen...a stupid man wanted to demantle it on his own with a "slijpschijf" (grinding disc) but we use it too for cutting bricks and iron...not sure how that is called in English...
but anyway the obus exploded and the man was dead... sometimes the Dutch are right about those stupid Belgians...but in the time it was nearly a sport to demantle old WWI obusses...I remember that on every mantel piece of the chimney there was a whole queu of cupper "douilles" as they were called (emty cartridge/shell)...seemingly the "oldies" in the time were cleverer than today...and yes that was only the polished ones...the rest was sold for the price of the cupper...
But Dirk, as soon as I have time, I will seek for you about the Waterloo battle field...and you know me I find everything ...as I found for you the Tsar family pretender in England...the BBC time.... now some 15 years ago...
Kind regards from Paul.