Inasmuch as it’s an outlier, the future of the Technical Standards and Regulations Directive (2015/1535/EU), which requires member states to notify the EU of any draft technical standards, remains unknown.
The issue remains relevant because in June 2019, the then-Culture Secretary, Jeremy Wright, blamed the Directive for why the rollout of age verification of adult content had to be delayed. (That of course is not the reason why, but any European port in a storm will do.)
What is interesting to me is that 2015/1535/EU contains the definition of “information society service” referenced across other pieces of EU legislation, including the Data Protection Bill 2018, which is the domestic implemenation of GDPR. Breaking the link to the Technical Standards Directive would be the means for the UK to redefine an ISS.