I am a grumpy old man, however I am not 'avin it that round your way there are groups of 8 year old's without a supervised, likely CRB checked adult.
I do at times see a few littlin's on their bikes and I feel slightly uplifted to see them, but my Wife tut's the way wifes can and she reminds me...
I dont think you will see any groups of 8-11 year olds, I am not sure of the current 'cut off age' that allows you to actually go out unsupervised, but this to me seems the reason that the aforementioned 'larks' no longer happen.
I am guessing that 11 or 12 years old might be the current age...