TjLaZer, look what CodeTapper wrote in an other forum, I couldn't say it better:
Actually AmiGer didn't change that - the original game has the main menu with the button "Practise" on it.
- Practise spelt with an s is the verb, meaning "to practise".
- Practice spelt with a c is the noun, as in "a practice".
Since there is no other text to work out which case Geoff Crammond meant, I actually think it implies the verb and therefore it is spelt correctly.
:-)