@neil
The list of sites closed as a result of the act in your section 'In Memoriam' will be a valuable resource for talking to MP's about the impact.
There must be loads of mutual help groups for medical conditions, owners clubs for vehicles, forums for tradespeople, etc that just exchange technical knowledge but would be worried about being in scope.
If they all get driven onto one of the big platforms because of OSA that would be a backward step for UK digital sovereignty.