From what I have seen of golden syrup (Lyle’s is available in some supermarkets here), the problem may be consistency: corn syrup is extremely thick. I doubt it will affect the cookies much - most such recipes are pretty tolerant, and the extra flavor may be a nice addition. With a pecan pie I could see it might be problematic, since you’re dealing with a custard base which might not set correctly if it’s too liquid.
On yorkshire pudding: we always make it for Christmas at my parents. Or rather, we make individual ones, quite like popovers. The difference is that YPs start with the drippings from the roast - a little bit in each tin - so they don’t pop quite so high. But they get such lovely flavor from the meat.
(I’ve a feeling our version is very non-traditional, but it works well for us. As for a single, large YP - Helene Hanff described it as a “smooth, high, empty waffle,” which is about as close a description as you can get.)
Now, for sausage seasonings: this runs all over the map in the U.S. (And I’m not even going to start on popular “ethnic” sausages, like bratwurst, kielbasa, chorizo, or andouille.) I’ve had everything from very bland to painfully hot, but the most popular seasoning seems to be a sage blend. It works nicely with mild pork.
As for butter in biscuits: it will work, but it must be cold when you cut it into the flour. If it isn’t, it will mix too much with the flour and make a heavy, doughy mess. Crisco has a somewhat higher melting point than butter, so doesn’t tend to cause this problem.
Kippers are a hideous way to begin the morning. I like fish, and a nice smoked salmon can’t be beat at an early hour. But to be confronted by fish that can only be described as smelling deeply, profoundly dead, sitting-out-in-the-sun-for-days-before-it-was-canned dead, is just cruel. I assume they are a holdover from boarding schools, which probably found them an effective disciplinary tool.