Turns out the UK government ran a second impact assessment on the Online Safety Act in October, which I didn't know about. They seemed quite surprised to learn that individuals might be running in-scope services.

(I did respond to the original consultation and I definitely told them this then...)

https://assets.publishing.service.gov.uk/media/6716222b9242eecc6c849b09/Online_Safety_act_enactment_impact_assessment.pdf#page=91

cc @neil