@Liverpool20
Thanks for your response. I've already set up parental filtering, having had to create an account to log in to the app and then call myself 'dad' to filter out the domains I don't want (mostly advertising). Honestly this is such a PIA in comparison to just blocking the specific URLs on the hardware, that I can only assume that TP link is forcing their users to sacrifice usability in favour of driving traffic to their app in hopes people will pay for a subscription.
Pretty terrible implementation too - the parental controls set to block those domains randomly blocked me completely from using the device at all earlier today. There was no timer or routine set to do so. I guess I'll see if I can live with it for the next couple of weeks, if not - back to Amazon she goes.