Nice tree diagram, but very American.

While I am not.

It was only meant linguistically, as I realized the verb is 'practise' in BE and 'practice' in American English

That's correct, Rosetree.

In the main varieties of English from outside North America, practice is the noun, and practise is the verb. For instance, we would say that a doctor with a private practice practises privately. There is no such distinction in American English, where practice is both a noun and a verb, and practise is not used at all. Canadian English also favors practise as the verb, but practice appears with relative frequency as a verb.