2019 was a quiet year for such site visits for me, however I would mention a visit to Creswell Crags with a couple of groups which included well-behaved younger children. The female guide was EXCELLENT in her informative and engaging manner. The kids learnt a lot, didn't get bored and the adults all clearly enjoyed the experience. A job done very well.
(We all realised on the way back to the visitor centre, that we were all visiting from various parts of Scotland!)