I've been having a look at travel insurance options, in particular 2 that have been mentioned on the forum - Travel Insurance Direct, and insure4less.
Interesting to note that terrorism is covered with insure4less - and it is by far the cheaper option (in our case $124.25 for the top cover compared to $150 for TID)
Looks like this may be the best option unless someone else can point out something I have missed.