I mentioned in another thread here that, as kids in the 1950's, two of us used to play in a crater known locally as "The Spinney", where a heavy aircraft of some type had crashed during the war. That shallow crater was full of bits of metal and other stuff amongst all the brambles and nettles. We found a lot of fairly large calibre ammunition, on badly corroded belts, that we took as souvenirs and showed off at school to our friends. It was quite possible that there were still human remains there as well, as the aircraft was in pretty small bits, scattered over a fairly large area.
As above, whether anyone had the time or resources to properly excavate a crash site at the time is debatable. There was a war on, and I would suggest that there was more effort put into recovering the remains of allied crews than of Nazi crews (and I'm reasonably sure the wreckage we were playing around with was most probably German, just because they was no real reason for an allied bomber to have crashed in that location just west of London).