Is Taking Seroquel With Lamictal Advisable For Sleeplessness?

I was diagnosed with BP II about ten years ago. After trying a few medications available at the time, I began taking Lamictal, building up to 300 mg a day. I still had trouble sleeping, so after a bad experience with Ambien, my doctor got me on Lunesta, which worked great. I have moved to a country that does not have Luniest, so I have had to use Xanax as a sleep medication. My doctor wants me to try taking Seroquel 25 mg along with the Lamictal to see if that will address my sleep issues and the level of anxiety/depression I occasionally stuffer from. Is is unusual to combine Lamictal and Seroquel? It looks like they treat the same symptoms. This is a new doctor for me; I have only seen him for a year, while I was with my doctor in the states for 15 years.