If you own a thatched property you realy should read this and take a look at the great work done by the thatch advice centre who have done some work at establishing fires in thatch properties and their causes.

Statistically, homes with thatched roofs are not more likely to catch fire than those with conventional roofs but, when theydo, it can cause severe damage to property and so receives a lot of negative publicity.
Historically the most people agreed the main cause of fires in thatch was the transfer of heat from the chimney,but this has not been proven by either research or forensic evidence. Through investigation carried out on 148 thatch fires the main proven cause was ejected embers  from either the chimney or a chimney fire.
Not only is it important to ensure your chimney is swept regularly(not only at the start of the season but also part way through) , but vital that you reduce the risk of embers being ejected from the stack.
ProSweep acknowledge The Thatch Advice Centre and recomend you visit theirwebsite for more details.