Question about roofs

One of you knowledgeable people might be able to help answer a question for us. We have to renew our building insurance, and one of the questions (which we haven't been asked before) is about what the flat part of the roof is constructed of. There are loads of options, the most likely being "asphalt" or "felt on timber". We're on Pemberton Road. Anyone know what it's most likely to be, or how we can find out?