Yep - in the UK it is entirely legal - there is simply no classification of "barely legal" - it is either legal or not.
ETA:
Just did a quick check for DVDs available in the UK, asked DuckDuckGo search for "UK sellers of pornographic DVDs", the first choice was this one:
View attachment 66584
On the page that came up, there was a search option, I type "barley" into the search option, this was the result - pixelization added by me:
View attachment 66585
Those are legally available in the UK with a BBFC classification that makes them legal to sell as DVDs.