Interested to know whether anyone in a CIL area has had to pay. I'm doing a conversion in Croydon (not a barn!) and am being charged £11000 even though on every other count I would qualify for Self-Build exemption.
Stop press.... Just found this...
https://www.boyesturner.com/article/boyes-turners-cil-victory-saves-self-builder-client-nearly-80000
You would need to contact them to get details of the case.
I note it was "settled" just before it went to court but even so it might be useful.