I'm with NRMA. The insurance is basically useless for contents, but overall trailer and structurally is all covered. I recently had a claim through them after my CT tent was flattened by a storm. Scarilly thay hardly understand what a CT is but their assessing company are great and it was cash settled in under a week.
They were around $270 for $12k CT + annex + contents insurance. I will be shopping around when policy is due though because I lose 20% off the no claim bonus after this claim