quite surprised that an airfield the size of LHR can't cope with that and still provide enough fire cover to at least keep one runway open.
Give them a break! When the alarm goes and the tenders are sent out, there isn't time to start asking if it is a little, medium of big fire.
I'm sure they will have everything back to normal as soon as is technically possible, positioning sectors from Luton are not good for anyone, nor are empty departure lounges.
One commentator already said fire not relating to previous 787 issues, but I wonder how much damage there is that can't be seen. Thankfully no injuries reported, but a hull loss so early on would not be good for the type.