We used Intasure, who specialise in holiday home insurance, for our building and contents insurance. Very quick and easy to set up with some good features for example travel costs if there is a serious problem at your apartment i.e. Flood / fire/ break in etc
It is also worth bearing in mind that you need specific insurance if you intend to rent your apartment out and a lot of companies do not cover this as standard.
website is www.intasure.com