Hello,
In 2010 i've held a vacation on Malta. The Lascaris War Rooms were open but they were restoring the plotting room at that time. Keep in mind that the entrance is found via the the Upper Barracca Gardens from Battery Street (Battery fires at noon a shot for time ref.) The tour bus of the north holds in sight of the battery while on the harbour side at noon, beware of weird faces when ur sprinting from the bus to make pictures and video of the shot
and others just missed it...).
It costs about €15 pp (currently more?) to ride the sightbus. Every half an hour it comes by and you can hop on and off. Local busses are a treat..cheap and quite a ride....
http://www.maltasightseeing.com
Lots of traces of WW2 can be found, i recommend the reading about Pedestal etc before you go.