At the fields that I instructed at, I had already worked out where the alternative landing sights were (as one of the airfileds, in particular was pretty good at suddenly closing following an 'incident').
It didn't, however, include any navigation to distant shores - the student was fully briefed on exactly what to do, and say, if the runway was suddenly denied to him/her by ATC.
A landing would be made at the base aerodrome - somewhere.
One circuit - one landing. "Go Around" at pilot discretion.
Homeguard - can you tell me which JAA Approved syllabus you are following when you teach navigation before first solo and circuit consolidation? The only approved one that I know of, off hand, is AOPA - which doesn't include navigation before first solo.
You are sticking to your flying order book and company operations manual, aren't you?