So what is the definition of "spontaneous" officially laid down by the guidance? (I knowmnit's downloadable from that link I gave earlier, but I haven't had a chance to do that yet.) From what you say about Morris dancing, Richard, it appears that it involves that spur-of-the-moment element, which means it is far more restrictive than is really justified.

"Acting, done, occurring, without external cause; voluntary, without external excitement...[f LL spontaneus (sponte of one's own accord)]. (Oxford Concise Dictionary)

Still, if there's a legally binding definition laid down it doesn't affect it even if it's completely off the wall, I accept that it's still what we have to work with. (Though would a questionable definition laid down in a guidance document, rather than in an Act, necessarily be legally binding?)