So just a reminder that barbecues as well as discarded cigarettes could cause a serious fire in the parks dry grass and woodland.
Even when conditions aren’t bone dry, fires can catch quickly and soon become out of control. A five-hundred-year old oak was once lost in Richmond Park due to a disposable barbeque being carelessly dumped.
Also note that if a barbeque is reported, a fire-engine will almost certainly be called to the scene which of course may affect response times to other more life-threatening incidents.
See also Royal Parks general notes on picnic rules for its various Parks. You may not be aware that there are maximum sizes for picnic parties, for Bushy park in particular this is 20.