In reply to phill bentham:
Ok everyone, here is an extract from an email I just received from the MLTA (advertising the "Turbo SPA" workshop)...
"We regularly have queries about the remit of the SPA. Mal Creasey, MLTE Technical Officer, has these words of advice:
'As an SPA teaching leading is out of your remit, however there are several things you can do to help someone to grasp the fundamentals of leading and in particular placing natural gear.
You can 'guide' clients, i.e. lead a route and have them second, you can have clients on a top rope whilst they place gear which you can comment on or 'score' as you lead/second the route, you can find suitable places at the foot of the crag where you can demonstrate good gear placements and they can learn by example.You can also demonstrate exactly how you set up a belay at the top of the climb, as if they had led the route.'"
Especially take note of the last sentence. That should answer the original question - if an MLTE Technical Officer says it's ok, then it's ok.