Paul and mattb are right, the standard (in NSW) is that trees of a certain height and width are subject to Council Preservation and can’t be lopped/trimmed or cut down without Council approval. In my area the size is a spread of 3 metres or more or height of 5 metres. This doesn’t apply to declared weeds.
Blocking views is irrelevant and if the OC had done anything to the trees they could have been reported to the Council for a breach.
I’m surprised a lawyer would send a letter like that.