It covers all dogs really if you read it and the 18 references are hardly like listening to a dogs trust home checker! Vet nurses have the neuter thing imprinted on them too. (I know you didnt say it )

There are loads of article and studies on behaviour and pyhsical changes after neutering, that was the first one. Given that the OP wants to neuter a PUPPY then I feel its very appropriate, especially in a working breed.

Just mooching about online, the recommended age for a dog seems to be 9 months?

Well 9mths is better than 12wks which is what Ive read in some places!!

I think to spay a Dane at 9mths would be wrong, but a JRT that mature physically very quickly, its not so bad, providing the dog has had a season first.

Yeah I think at 'weeks' old is too young.

BTW, the lady who said the thing about the growth plates isn't a 'home checker' - she runs the Freedom Project (with two other people) and is an experienced vet nurse and canine hydrotherapist (not sure why I feel I have to defend her but I do ).

I guess, if the OP trusts her vet then she should take his advice.

If she is your friend I fully understand you defending her.