Active job

Advice

I just have a question for all you roofers out there. What is the minimum width that flashing needs to be on a colour steel roof? I had my half of a brick and tile unit re-roofed. (old decramastic tiles removed) The neighbour didn't want her side done and is now claiming the flashings the roofer used are half the required width for a join. How would i go about finding this out and how would I check it.? Thank-you!