Definitely doesn't shy away from doing it! But one thing I find most irritating is that it seems reluctant to say it proud and loud.
Look at the situation with 4chan and Kiwifarms. They are basically asking to be blocked from the UK and they refuse to. I can't really say why the onus is put on the websites to enact blocks, but my suspicion is the government doesn't like the idea of displaying an official page stating that you are not allowed to see something because the government doesn't want you to.
They don't even have to do that, the connection can just be left to time out on the client side. This is what they did (and some ISPs still do) for the Internet Archive...
Yes, archive.org is classed as an adult site in the UK.
Browsing with a VPN is a frustrating experience. They are abused by many of their users which leads to circular capture checks and straight blocks.
It seems like your VPN setup has a leak, or the real location is obtained otherwise through the operating system (locale setting or GPS).
I would be surprised if your locale leaked on GrapheneOS for example.
I've never had this issue (using Private Internet Access on iOS).
Going the other way around to try and watch British TV I used to find with a normal hosted VPN services could still figure out I wasn't in the country, but now I have a Tailscale exit node at my mum's place in the UK it always works fine.
So I suspect it all comes down to the IP source, probably a residential IP is the best possible case and with commercial VPNs it depends on how hard they work on isolating their IP blocks from known datacentres.
You would need to get your sim card out of your phone and use wifi or buy one of them foreign esim
For vpns I actually found that websites that block vpns for some reasons are worse at detecting commercial vpns than when you deploy your own on vps
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Also I forgot about other things. When my phone for some unknown reason had its region set as GB, I had British ads in YouTube music