The UK did not go through with the porn block. You can perfectly well set up an account without any NSFW filtering, and as far as I can remember, it wasn't even 'opt out'. I'm with Virgin--oh the irony--and have never had any filtering.
If it happened to you, perhaps you just happened to set up your ISP when there was _talk_ of the bill, but ultimately it didn't pass.
"UK's controversial 'porn blocker' plan dropped": https://www.bbc.co.uk/news/technology-50073102