The same leaflet that actually answered my original question and I quote:
d) In determining the direction of yaw for an inadvertent spin the turn needle is always the best indication (not slip ball). Beware if you only have a turn co-ordinator, it measures yaw and roll. In an inverted spin yaw and roll are in opposite directions so the turn co-ordinator is of no help to you here!
I knew I had read it somewhere and that's all I was after.
Certainly the rest has been stimulating enough, but I wasn't actually asking for a generic recovery technique, though I can see the handling notes for the aircraft I'll be spinning is close to PARE. I'll be watching out to see if I can feel the rudder in the spin, sounds though from the pilot's notes in a true spin the rudder may feel very light for the given type. I'll have to see.