The Steepest Street in the World

Here’s an interesting fact. I suffer under the impression that Wales gets overlooked, that we punch below our weight on the world stage. It would be interesting to see how often Wales is mentioned in world media as opposed to, say, Israel or Slovenia, which are about the same size. I guess it’s less.
If I’m driving down from town to the Morfa I prefer to use Llech, because I’m less likely to meet oncoming traffic (because it’s one way). Yes, it’s steep, but I have four wheel drive and anti-lock brakes. But I wondered — just how steep is it?
So I looked up Wikipedia and the Guinness Book of World Records. The steepest street in the world is … Baldwin Street in Dunedin, New Zealand! Yay! Another record for the Kiwis!
At its maximum, the slope of Baldwin Street is about 1:2.86 (19° or 35%). That is, for every 2.86 metres travelled horizontally, the elevation changes by 1 metre.
Hang about.
I looked up Llech, or Ffordd Pen Llech as I discovered it’s also called, on Wikipedia. It says; “Its descent of the rock spur to the north of the castle gives it a tangentially measured gradient at its steepest section of 1:2.73. Whilst this translates to the vertical rise being 36.63% of the horizontal going, it is normal practice for UK highway authorities to round gradients to a nominal figure to avoid confusing road users with excessive precision; hence the warning sign gives a slope of 40%.”
And Llech carries on up through Twtil to Pen Dref, also quite steep.
1:2.73 is steeper than 1:2.86.
36.63% is steeper than 35%.
Clearly, Ffordd Pen Llech in Harlech is steeper than Baldwin Street in Dunedin. So can we have the world record now please?