Thanks to a thread started in chat www.mumsnet.com/Talk/_chat/a2091314-If-a-child-wanted-to-learn-coding?msgid=48787018#48787018 a few months ago, I followed the recommendation of UnrelatedToElephants and found out about this recent computer coding week: youngrewiredstate.org/. The organisation has won prizes for its activities, which essentially are all about peer learning of computer coding, led by people in the industry.
It was thanks to this that DS signed up and attended a local centre for five days, developing a site in a team and went on to the Festival of Code over the weekend. He went in knowing some basic coding and made incredible progress, learning new languages and also having the fantastic experience of attending the weekend event and discovering hundreds of boys and girls with similar enthusiasims. The week was very well run and - incredibly - all free other than the (subsidised) coach fare. I highly recommend it to any parent of youngsters interested in computing at any level. Though it's another year to the Festival of Code, which you can register for now there are other events during the year and they will do school assemblies and other such activities.
I've posted this in the original chat thread, but I thought I'd post here in case the Chat thread disappears.