@Simon
You remember that Yorshire pudding originates from Nottinghamshire? How old are you exactly? The now legendary pud is hundreds of years old.
Some would have you believe it comes from France (Fanny Craddock for one*). While other will tell you that it was introduced to France by the Normans who were of course of Viking descent, and that the Normans who came to France via britain actually took the recipe to France from britain. Then there are those who claim that the recipe is actually a Viking one, and so on and so forth.
Nobody really knows where it came from and many areas of the country have tried to claim it as their own usually on the grounds that "my great, great granny used to make them and she's from Cardiff" or some other solid proof of origin. The same is true of the likes of the Cornish Pasty. The reason they are called Yorkshire puddings is probably down to the Yorkshire tradition of the big pud as starter. Even as a Tyke I don't believe the pud originated here.
And of course discovering the earliest know recording of the recipe would prove nothing. Who is to say that the writer didn't simply copy an already tradtional receipe.
And there are many variations on the receipe, how well the pudding rises depends on the combination of oven and receipe. I have found that moving from a gas oven to an electric fan oven has forced me to modify my receipe for the best product. And then there is the matter of the size of the pudding. Larger puddings must be cooked at a lower temperature or the edge of the pud will burn before it is fully cooked. The perfect pud comes with experience.
I was given the following as a starting point years ago. One or more eggs depending on the desired amount of batter. The same volume of plain, weak flower as egg. The same volume of liquid as egg. Salt to taste.
The liquid is a matter of taste, some like milk, some find water to be better and some prefer a mixture. You certainly wouldn't want to use proper fresh milk without any water, but the watery stuff they sell in supermarkets these days would be OK on it's own.
The very fact that the proportions vary so much from one recipe to the next would seem to demonstrate that the proportions aren't critical anyway.
DON'T cool the batter in the fridge. DON'T use a blender to mix it, do it slowly. And definitely DON'T open the oven door until the puds are cooked.
Paris is a bit of pudding isn't she?
* I can't hear that name without thinking - "Now all your doughnuts will be like Fanny's"