With soem 400hrs on Bulldogs,and living under the Old Sarum circuit - in fact I am just penning off a fax to get them to do an intial trip for my daughter to include a spin (!)- on London UAS all those years ago - gawd nearly 25 - we found each aircraft was sensitive to fuel load, single crew of dual,and of course which way you span it - it was hard work to spin R but IIRC semed to posesses some very strange characteristics. We were on a summer camp IIRC when the Southport beach fiasco occurred. As a dumb stude,so long as you remained positive in entry and positive in exit, on the whole there was never a problem. The problems arose because the stude was afraid to make the aircraft work for him, and so it went off on an aerodynamic jaunt of its own!
The hairiest I ever had was doing the aero's competition (practice) at height (usual recovery by TA + height of ground). this involved a quarter rolling circle, which if you really wanted to cock up in the early days you could use as an inverted entry to a spin. Usually you were running out of energy as you went round anyway and if you kept the nose too high in the rolling entry, you could wash a load of kts off v quickly.
Ah, sunny days with oil under the aircraft.