I wonder whether very traditional maths, where all the working out is written out in full in words, isn't easier for the clever child with a preference for words over numbers?
Huh? Which mathematicians write things out in full in "words"?
The opposite is true. Mathematicians introduce mathematical notation to write e.g.
{z: |z-a| = b}
instead of writing a sentence "The set of (complex) numbers z such that the modulus of z minus a is equal to b."
Mathematicians frequently define new words to avoid writing out longer sentences e.g. "f is a meromorphic function" instead of "f is a holomorphic function with a finite number of isolated singularities".
What on earth is the benefit of writing maths out in "longhand" and not using mathematical notation/terminology ?
Logic and using words are completely different things. Higher level school maths in the UK definitely requires logic but that logic does not necessarily need to be expressed in a lot of words.