Sea-level 100.000 years ago was 50 - 100 meter below current sealevel; there was no Northsea. The Netherlands and Brittain were connected through Doggersland.
Beach, Maasvlakte2
Piece of mamal bone. Estimated age: 65.000 years (Early Weichselin)
Fossilized oyster (Ostrea Edulis). Estimated age: 15.000 years (Holocene)
You can check your collected material here: https://www.oervondstchecker.nl/alle-vondsten
Nothing to do with radio, but not only radios are fascinating.