I was told by the live chat agent that in the 'hold' year any SP earned don't count (so, for example, I'm flying to Sydney tomorrow for a night and that flight is earning SP but the SP won't count for anything).

That seems pretty fair as the system gives you a guaranteed second full year of Elite in which to requalify normally thereafter. Would be far too generous if it allowed you to bank up over effectively two years what everyone else has to do in one.