Is it the airfield that is licensed or the runway? Just wondering as some licensed airfields also have unlicensed runways
Yes, fun isn't it. I tried to read up on this stuff a while back and came to the conclusion that there is no simple answer.
There are many reasons why a licensed airfield might have an unlicensed runway, including but I'm sure not limited to:
(1) The runway fails to meet all 827 criteria for being licensed, eg the telegraph poles along the road at the end of the runway are 2mm too tall.
(2) Nobody has a clue whether the runway meets all the 827 criteria, because the airfield operator has made a business decision not to fork out vast sums of money for a survey because the extra income from having the new runway licensed as opposed to unlicensed won't cover the costs.
(3) The airfield operator has deliberately decided not to bother to license a runway because they see no need, because you only need a licensed runway for training, and they've got another perfectly good licensed runway, and there would be noise issues if people started flying circuits on the new runway they've just mown.
You can probably make up several more of your own. A few real reasons from airfield operators might be instructive!