That's why I was limiting my query to English bikes. I know my selection would be limited, but at least the measurements might be more standard.
when I look for bikes online I generally look at the stem as an indication of frame size and assumed the Dawes would be about right.

But in my excitement and naiveté I neglected to check standover height which turns out to be a bit high for me.

The actual frame size seems to be 23". I would need a 21" as measured by this method: